Question:
How is force related to momentum of a body?
Answer:
Force is directly proportional to the rate of change of momentum.
Force and Laws of Motion
Q 1.
While driving on a highway, an insect strikes on the car windshield and splatters. Which experiences greater impact (force): an insect or the windshield?
Q 2.
On what factor does inertia of a body depend ?
Q 3.
Do action-reaction forces produce the same magnitude of acceleration ?
Q 4.
Fill in the blanks :
The study of motion of a body under the action of a force is called ______.
Q 5.
In the above question, which body is damaged more ?
Q 6.
Using second law of motion, derive the relation between force and acceleration.
Q 7.
What is the unit of force in c.g.s system?
Q 8.
A TV set is lying on a table. The TV set experiences a gravitational force (pull) downwards (FW) by the Earth. It also experiences a force on it due to table in contact i.e. (FTable-TV) in upward direction. Do these forces form an action-reaction pair? Do these forces follow Newton's third Law of motion?
Q 9.
Are action-reaction forces simultaneous ?
Q 10.
Explain why a player lowers his hands while catching a cricket ball.
Q 11.
Can balanced forces change the shape and size of an object?
Q 12.
Can every force produce motion in every object?
Q 13.
The masses of two objects are 2 kg and 20 kg. Which has greater inertia ?
Q 14.
Can balanced forces change the shape and size of a body ?
Q 15.
A car weighs 1500 kg.Its speed time graph is shown in Fig. Calculate the force required at the end of 5 seconds to bring the car to a stop within one second.
Q 16.
When a branch of a tree is shaken, some of the fruits may fall down.Why ?
Q 17.
What acceleration is produced by a force of 5 N acting on a body of mass 20 kg ?
Q 18.
It is difficult to balance our body when we accidentally slip on a peel of banana. Explain why?
Q 19.
What is the total momentum of a bullet and a gun before firing?
Q 20.
A body of mass 25 kg has momentum of 125 kg m/s. What is the velocity of the body?
Q 21.
What is the SI unit of impulse.
Q 22.
An object experiences a net zero external unbalanced force.Is it possible for the object to be travelling with a non-zero velocity ? If yes,state the conditions that must be placed on the magnitude and direction of the velocity.If no,provide a reason.
Q 23.
Explain what is meant by momentum of a body.Is it a scalar or a vector ? What are its units ?
Q 24.
Fill in the blanks :
Newton's second law of motion states that the rate of change of ______ of a body is directly proportional to the force and takes place in the same direction as the ______.
Q 25.
Fill in the blanks :
An umbrella protects us from rain it is based on the property of _____________.
Q 26.
What did Galileo conclude on the basis of his experiments on the motion of objects?
Q 27.
A force of 5 N gives a mass
an acceleration of 10
,and a mass
,an acceleration of 20
.What acceleration would it give if both the masses were tied together ?
Q 28.
Two objects of masses 100 g and 200 g are moving along the same line in the same direction with velocities of 2 m/s and 1 m/s,respectively.They collide and after the collision, the first object moves at a velocity of 1.67 m/s in the same direction.Determine the velocity of the second object
Q 29.
In the above question,which body undergoes greater change in momentum ?
Q 30.
Honey and Sunny are two friends.Both are financially well off.Honey is fond of driving an SUV while Sunny enjoys driving Tata Nano.Honey explains to Sunny the risks of driving a light vehicle and Sunny explains to Honey the cost factor.
Read the above passage and answer the following questions :
(i) With whom do you agree,with Honey or with Sunny?
(ii) Explain, why?
(iii) Which values of life do you learn from this discussion?
Q 31.
Is force required to keep a moving object in motion (yes/no)?
Q 32.
What are contact forces? Give examples
Q 33.
A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 metric tonnes. (Hint: 1 metric tonne = 1000 kg.)
Q 34.
Fill in the blanks :
On what factor does the inertia of a body depends? ____________
Q 35.
Which law of motion gives the measure of force?
Q 36.
What are unbalanced forces?
Q 37.
Do action and reaction act on the same body?
Q 38.
Why mass is sometimes called coefficient of linear inertia?
Q 39.
A certain force exerted for 1 -2 s raises the speed of an object from 1.8 m/s to 4.2 m/s. Later,the same force is applied for 2 second. How much does the speed change in 2 s ?
Q 40.
A feather of mass 10 g is dropped from a height.It is found to fall down with a constant velocity.What is the net force acting on it ?
Q 41.
A bullet of mass 10 g travelling horizontally with a velocity of 150
strikes a block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block.Also, calculate the magnitude of the force exerted by the wooden block on the bullet.
Q 42.
What is the total momentum of the bullet and the gun on firing ?
Q 43.
What is one newton force ?
Q 44.
Name any two applications of the law of conservation of linear momentum.
Q 45.
State Newton’s first law of motion. Hence define force and inertia.
Q 46.
Name the categories of forces based on interaction.
Q 47.
How Newton's Second law of motion is different from First law?
Q 48.
An object of mass 1 kg travelling in a straight line with a velocity of 10 m/s collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the
same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.
Q 49.
The following is the distance-time table of an object in motion:
| Time in seconds |
Distance in meters |
| 0 |
0 |
| 1 |
1 |
| 2 |
8 |
| 3 |
27 |
| 4 |
64 |
| 5 |
125 |
| 6 |
216 |
| 7 |
343 |
(a) What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?
(b) What do you infer about the forces acting on the object?
Q 50.
Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of 0.2m s-2. With what force does each person push the motorcar?
(Assume that all persons push the motorcar with the same muscular effort.)
