Name the unbalanced force which slows down a moving bicycle when we stop pedalling it.

Write the formula to find the magnitude of gravitational force between the earth and the moon.

A racing car has uniform acceleration of 4 m/s2. Find the distance covered by it in 10 seconds after start ?

When a body moves with constant velocity, what is the magnitude of net force? Is the magnitude of force applied to keep the body moving, equal to, less than or more than frictional force? Explain

The ratio of the gravitational force on Neptune to the gravitational force on earth is 9:8. Ramesh weighs 792N on Earth. Calculate his weight on Neptune?

Write the difference between distance travelled by a body and its displacement. An ant travels a distance of 12 cm from A to B and then moves a distance of 9 cm at right angle to AB. Find the resultant displacement and the total distance covered by it.

Explain the following type of motion with one example for each :

(a) acceleration is in the direction of motion.

(b) acceleration is against the direction of motion.

(c) acceleration is uniform.

A boy on a 78.4m high cliff drops a stone. One second taker, he throws another stone downwards with some speed. The two stones reach the ground simultaneously. Find the speed with which the second stone was thrown.

Give reasons for the following :

(a) Bicycle begins to slow down when we stop pedalling.

(b) When a force acting on a body has equal and opposite reaction, then why should the body move at all ?

(c) Between a five rupee coin and a one-rupee coin, five rupee coin has more inertia.

(d) An athlete runs a certain distance before taking a leap.

(e) At times an object does not move even when forces are acting on it

State the law of conservation of momentum. Mention two factors which determine the momentum of a body.

A ball of mass 0.4 kg is thrown vertically upwards with a velocity of 10 m/s. What will be its initial momentum and what would be its momentum at the highest point of its reach? If this change in momentum occurs in one second, find the negativelyaccelerating force acting on the ball, when it was going up.

A heavy person experiences more sideways push when a moving vehicle turns suddenly. Why ?

Mass of an object is 5 g on the moon. What will be its weight on the earth ? (g=10ms2)

Which accident will be more damaging, collision between two trucks moving with a sped of 50km/hr. or collision between two cars moving with a speed of 50 km/hr.? Explain.

A tourist drops a rock from rest from a ground rail overlooking a valley. What is the velocity of the rock offer 4.0 sec? What is the displacement of the rock aften 4.0 sec?

On a position-time graph, draw three lines/curves to represent the motion of an object :

(a) remaining at rest.

(b) moving very slowly.

(c) moving very fast.

A car of mass 1000 kg moving with a velocity of 40 km/h collides with a tree and comes to a stop in 5 s. What will be the force exerted by the car on the tree ?

(a) Draw a position-time graph for an object in uniform motion. Show that the slope of the position-time graph gives the velocity of the object.

(b) Differentiate between distance and displacement. Length of the hour hand of a clockis R. Find the distance and displacement between 12 and 12.30.

Give an example of a uniform circular motion

Write the value of acceleration produced in a freely falling body.

A tourist drops a rock from rest from a ground rail overlooking a valley. What is the velocity of the rock offer 4.0 sec? What is the displacement of the rock aften 4.0 sec?

Define inertia? What determines the inertia of a body? Between a foot ball and a rock of same size which will have more inertia?

(c) How much time will it take to finally stop ?

In the collision between a heavier body and a lighter body, if the force experienced by the heavier body is F1 and that by the lighter body is F2, write the relation between F1 and F2.

Under what condition will the magnitude of displacement be equal to the distance travelled by an object ?

Grass looks green, papaya appears yellow. Which cell organelle is responsible for this ?

Write the structural features of this organelle.

What is meant by uniform velocity and variable velocity ? Explain giving an example of each.

The Newton’s second law of motion is often seen in action in our everyday life. Give three experiences of your own.

Give reason :

(a) What is meant by acceleration due to gravity ?

(b) Value of „g‟ is not constant on earth.

(c) Objects with different masses take same time to fall from a fixed height.

(d) „G‟ is known as gravitational constant. Write its SI units.

Explain recoiling of gun on the basis of Newton’s Third Law of Motion. A bullet of mass 20 g is horizontally fired with a horizontal velocity

150 m/s from a pistol of mass 2 kg. Calculate the recoil velocity of the pistol.

What is the SI unit of the universal gravitation constant (G)?

Note the relationship between the first two terms and accordingly, fill in the blank.

(1) Salivary gland : Glandular Epithelium : : Respiratory tract : __________

(2) Flexibility : Collenchyma : : Hardness : __________

(3) Cutin : Epidermis : : Suberin : __________

(4) Plasma : Blood : : Axon : __________

A car travels 100 km distance at a speed of 60 km/h and returns with a speed of 40 km/h Calculate its average speed for the whole journey.

A ball is thrown vertically upwards and it returns to the thrower after 6 sec ( g=9.8 m/s2) Find.

(i) The velocity with which it was thrown up.

(ii) The maximum height it reaches

(iii) Its position after 4 sec.

Draw a velocity-time graph for the motion of an object having.

(a) positive velocity and negative uniform acceleration.

(b) positive velocity and positive uniform acceleration.

(c) positive velocity and zero acceleration.

(i) If the force of gravity on Mars is 3.8 ms-2, then what would be the weight of an object on mars which has a mass of 10kgs on earth?

(ii) What would be its weight on earth?

(iii) From the above data, analyse what will be the percentage difference of your weight on earth and on mars?

In which one of the following cases will the distance covered and the magnitude of the displacement are not the same ? Justify your answer.

(a) An athlete completes one lap in a race.

(b) A raindrop falls in vertically downwards.

(c) A passenger in a train travels from Delhi to Mumbai which goes via Rajasthan.

When a sailor jumps out of boat in forward direction the boat moves backward. Explain the reason for this observation and state Newton’s law governing this observation.

A bullet of mass 10g travelling horizontally with a velocity of 150 m/s strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block.

An artificial satellite revolves around the earth with a constant velocity. Is the statement true ? Justify your answer.

What is the effect of change of pressure on physical state of matter ? Explain with an example of a gas.

An object is thrown vertically upwards and rises to a height of 10 m. Calculate the velocity with, which the object was thrown upwards.

A body of mass ‘m’ is moving with a velocity ‘u’. When a force is applied on it for time t, its velocity increases to ‘v’. Write expressions for :

(a) Initial and final momentum

(b) Change of momentum

(c) Rate of change of momentum. Also write SI unit for each.

Explain giving reason :

(i) If a stone held in hand is released, it falls towards the earth.

(ii) Two objects kept in a room do not move towards each other as per the Universal Law of

Gravitation .

Define uniform speed and uniform acceleration.

The train ‘A’ travelled a distance of 120 km in 3 hours whereas another train B travelled a distance of 180 km in 4 hours. Which train is travelling faster ?

A certain force exerted for 1.2 s raises the speed of an object from 1.8 m/s to 4.2 m/s. Find its acceleration. If mass of the object is 5.5 kg, calculate the force applied.

(a) A force of 20 N acts upon a body whose weight is 9.8 N. What is the mass and acceleration produced in the body ? (g9.8 m/s2)

(b) Write any one difference between mass and weight of a body.

(a) Freely falling body is the example of non-uniform motion. Explain this statement with reason. How much change occurs in velocity in 1 s ?

(b) A particle is moving along a circular path of radius r with uniform speed. Draw the directions of velocity of the particle, when it is instantaneously at point P. If the radius of ciruclar path is r, and it takes t second to complete one round, find relation for its circular velocity. Give its two examples.

Direction – tangent at point P

circular velocity – 2 pi r / t

The displacement – time graph of a body is parallel to time axis. What will you infer about the velocity of the body ?

A body of mass 10 kg is moving with a velocity of 20 ms1. A force is applied on the body for 25 s, and it attains a velocity of 40 ms1. Calculate the force applied.

Name the tissue found in the following locations :

(a) Haversian canal

(b) Chondrocyte

(c) Eosinophils

Give one function of each of these.

Please check NCERT Page 76 diagrams

Find what happens to the gravitational force between two objects when :

(i) Distance between them is doubled.

(ii) Masses of both the objects are doubled.

Define the term uniform acceleration. Give one example of uniformly accelerated motion. A bus decreases its speed from 72 km h1 to 54 km h1 in 5 s. Find the acceleration of the bus.

Describe an activity with diagram to explain conservation of momentum.

(a) A body thrown vertically upwards reaches a maximum height h. It then returns to ground.

Calculate the distance travelled and its displacement.

As body comes back to its initial position,So Displacement is zero.

Distance travelled is 2h because It goes up h and returns h.

(b) In a long distance race, the athletes were expected to take four rounds of the track such that the line of finish was same as the line of start. Suppose the length of the track was 200 m.

(i) What is the total distance to be covered by the athletes ?

(ii) What is the displacement of the athletes when they touch the finish line ?

(iii) Is the motion of the athletes uniform or non uniform ?

If the force acting on a body are of following type, then describe their effect on the body :

a) Force of gravity < air resistance

body will keep on floating

b) Force of gravity > air resistance

body will fall quickly due to gravitational force

c) Mechanical pull on a bike > frictional force

bike will move

d) Frictional force = mechanical push on an object

object will remain still

e) Action and reaction force.

3rd law – same

we know velocity = displacement / time and we know AB is the shortest path. therefore , AB that is displacement will be used to find velocity

(a) Derive the expression for „G‟ with respect to „F‟.

(b) Why the weight of any object becomes less on moon as compared to the earth ?

Explain three applications of conservation of momentum.

1. When a cricketer hits a ball, there is a change in momentum of the ball due to which it goes out for a six.

2. A rocket moves forward by conservation of linear momentum.

Mona weighs 423 N on Earth and 1000 N on the planet Jupiter. What is the gravitational force on Jupiter? (g= 10ms2).

this question is not clearly given. gravitational force is force so answer should be 1000 N

but, solution 2 could be

let’s take g of earth as 10

1st

we hve to calculate the m

F = mg

423 = m x 10

m = 423 upon 10

m = 42.5

2nd g on jupiter

F = ma

1000 = 42.5 x g

g = 1000 upon 42.5

g = 23.52 (approx.)

(i) It is difficult to hold a hose for a fireman when it ejects large amount of water.

(ii) When an athlete comes running from a distance, he is able to jump longer.

(iii) It is difficult to walk on a slippery road.

A man’s weight when taken at the poles is 600N. Will his weight remain the same when measured at the equator ? Will there be an increase or decrease is his weight ? Explain.

(a) What is meant by uniform circular motion ? Give its two examples.

(b) A train leaves New Delhi railway station at 09 : 00 AM and reaches Jaipur, which is at a distance of 260 km at 12 : 45 PM. The train reaches Alwar (at distance 150 km from New Delhi) at 11 : 30 AM and stops there for 15 minutes.

(i) What is the reference point for the motion of the train ?

New Delhi railway station

(ii) What is the average speed of the train between Alwar and Jaipur ?

average speed = distance/time

= distance between alwar and jaipur/time

= 260 – 150 / 12:45 – 11:30

Name the connective tissue :

(i) Which are embedded in hard matrix of calcium and phosphorus compounds

(ii) Which connects muscles to bones

(iii) With fluid matrix containing proteins, salts and hormones.

(iv) Which stores fats below the skin and between internal organs.

(v) Which is present in the nose, ear, trachea and larynx.

(vi) Which connect two bones with each other.

During arm wrestling, participants put their arms on the table, and wrestle with the palms. If the force exerted by both the players is equal, (a) Where are balanced forces acting?

palms

(b) Where is the action reaction force pair acting?

on the table

(a) A force of 20 N acts upon a body whose weight is 9.8 N. What is the mass and acceleration produced in the body ? (g9.8 m/s2)

Weight of the body(W) = 9.8 N Acceleration due to gravity on Earth(g) = 9.8 m/s2 Hence, mass of the body(m) = 1 kg (W= mg or, m = W/g) Force exerted on body(F) = 20 N We know, F= ma Acceleration produced in the body(a) = F/m = 20/1 = 20 m/s2

(b) Write any one difference between mass and weight of a body.

already discussed

A particle moves over three quarters of a circle of radius r cm. Calculate the magnitude of its distance and displacement.

Here the particle has moved from point A to point B in an anticlockwise direction (shown by arrows). The net displacement in this case will be equal to AB (distance between initial and final position).

now, in triangle AOB, according to the pythagoras theorem

AB^{2} = OA^{2} +OB^{2}

or

AB^{2} = r^{2} + r^{2}

thus, the displacement will be

AB = r√2

distance – 3/4 * 3 pi r

Name the physical quantities denoted by :

(a) the slope of the distance-time graph

(b) the area under velocity-time graph

(c) the slope of velocity-time graph

Do action and reaction act on the same body or on different bodies ? Explain your answer with the help of example. How are they related in magnitude and direction ? Write the total momentum of the gun and the bullet before firing.

The position-time graphs of two objects A and B in three different situations for a particular duration are as shown below.

Draw a diagram showing a stone describing a circular path with a velocity of constant magnitude. Also show the direction of the force acting on the stone. Also mark the direction of the velocity at any instant of time.

Analyse the significance of specialised epithelial tissue present in the following :

(a) Ciliary columnar epithelial in respiratory tract

(b) Stratified squamous epithelium in skin

(c) Cuboidal epithelium in kidney tubules (d) Columnar epithelium in inner lining of intestine (e) Squamous epithelium in lining of oesophagus.

(a) A planet has mass five times of earth and radius three times that of earth. Calculate its acceleration due to gravity, if the value of „g‟ on earth is 10 ms2.

(b) Differentiate between „G‟ and „g‟.

A motor car of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Calculate the acceleration and change in momentum of the car. Also calculate the magnitude of force required.

*Initial* velocity = u =90 km/h = 25 m/s

Final velocity = v = 18 km/h = 5 m/s

time taken for the change = 4 sec

Acceleration = a = ( v-u)/t = (5-25)/4 = – 5 m/s^{2}

Unbalanced force required = mass* acceleration = -1200*5 = -6000 Newtons

Negative sign shows that force is opposite to motion and retarding the motion.

Change in momentum = mv-mu = m(v-u) = 1200(5-25) = -1200*20 =-24000kgm/s

(a) A scooterist covers a distance of 3 km in 5 minutes. Calculate his speed in : (i) m/s

(ii) km/h.

(b) Ramesh observes that at the start of his journey odometer of his car was showing 1080 km and when he reached Meerut it was showing 1330 km. If he took 4 hours to reach Meerut, find average speed of his car in km/h and m/s.

d. calculate the speed of the car during uniform motion

A man is standing at the top of a 60 m high tower. He throws a ball vertically upwards with a velocity of 20 m/s. After what time will the ball pass him going downward ? How long after its release will the ball reach the ground ? (g10 m/s2)

v = 0

u = 20 m/s

a = 10 m/s^{2}

The ball is thrown upward so, taking the downward direction as positive,

v = u – at

0= 20 – (10 X t)

10 x t = 20

t = 2 s

So same time would be taken to reach the man

The ball will cross him after 2 x 2 = 4 s.

Distance the ball travel while going to its upward highest point.

s = ut – 1/2at^{2}

s= (20 x 2 ) – (1/2 x 10 x 4 )

s = 40 – 20

s = 20 m

Now , distance from ground = 60m + 20 m = 80 m.

u = 0 m/s

So, time taken to reach ground :

s = ut + 1/2 at^{2}

80 = ( 0 x t ) + 1/2 10 x t^{2}

80 = 5 x t^{2}

t^{2 = }80/5

t = 16^1/2

t = 4 s

State the relation between „g‟ and „G‟.

(b) Find his average velocity if he covers each metre in 1 s.

A physical quantity ‘X’ is identified as rate of change of velocity. Identify ‘X’. Write its SI unit. Starting from a stationary position, Rahul pedals his bicycle to attain a velocity of 6 m/s in 30 s. Then he applies brakes such that the velocity of bicycle comes down to 4 m/s in the next 5 s. Calculate the acceleration of the bicycle in both the cases.

Total momentum of two bodies remain unchanged before and after the collision. Justify this statement.

In the collision between a heavier body and a lighter body, if the force experienced by the heavier body is F1 and that by the lighter body is F2, write the relation between F1 and F2.

A body of mass 10 kg is moving with a velocity of 1 ms1. Find (i) The magnitude of the force required to stop the body in 10 s. (ii) The distance the body will move through before coming to rest.

A man’s weight when taken at the poles is 600N. Will his weight remain the same when measured at the equator ? Will there be an increase or decrease is his weight ? Explain.

average speed = total distance/total time = 14/ 10 = 1.4

average velocity = net displacment / time = 4/10 = 0.4

A ball is dropped from the edge of a roof. If takes 0.1 sec to cross a window of height 2.0 m, Find the height of the roof above the top of the window.

The brakes applied to a train produce an acceleration of 5 m/s2 in the opposite direction to the motion. If the train takes 6s to stop after the application of brakes, calculate the distance it travels during this time.

(a) What is meant by composite fish culture?

(b) What is the basis of selecting the different species of fish?

(c) Which method is used to get pure fish seed?

Derive Newton’s first law of motion from the mathematical expression of the second law of motion.

Name the physical quantity which corresponds to the rate of change of momentum. An unloaded truck weighing 2000 kg has a maximum acceleration of 0.5 m/s2. What is the maximum acceleration when it is carrying a load of 2000 kg ?

A stone weighs 490 N on a planet whose acceleration due to gravity is one -half of the earth’s, value. Calculate.

(i) Mass of the stone

(ii) Weight of the stone on earth.

A physical quantity ‘X’ is identified as rate of change of velocity. Identify ‘X’. Write its SI unit. Starting from a stationary position, Rahul pedals his bicycle to attain a velocity of 6 m/s in 30 s. Then he applies brakes such that the velocity of bicycle comes down to 4 m/s in the next 5 s. Calculate the acceleration of the bicycle in both the cases.

From a station ‘X’ a train starts from rest and attains a speed of 54 km/h in 10 s. Then by applying brakes negative acceleration of 2.5 ms2 is produced and it stops at station ‘Y’ in 6 s. Find the distance between station ‘X’ and ‘Y’.