Question:
Define momentum.
Answer:
Momentum is a physical quantity defined as the product of mass multiplied by velocity. i.e. p = m × v
Force and Laws of Motion
Q 1.
What is the total momentum of a bullet and a gun before firing?
Q 2.
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 3.
Using second law of motion, derive the relation between force and acceleration.
Q 4.
A hammer of mass 500 g, moving at 50 m/s, strikes a nail. The nail stops the hammer in a very short time of 0.01 s. What is the force of the nail on the hammer ?
Q 5.
A person in a bus tends to fall backwards, when it starts suddenly ?
Q 6.
Can balanced forces change the shape and size of an object?
Q 7.
Are action-reaction forces simultaneous ?
Q 8.
Define momentum of a body.
Q 9.
Explain why a player lowers his hands while catching a cricket ball.
Q 10.
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 11.
Name the principle on which a rocket works.
Q 12.
Name the physical quantity that corresponds to the rate of change of momentum.
Q 13.
Which principle is involved in the working of a jet plane?
Q 14.
Is force a scalar or a vector ?
Q 15.
Can balanced forces move a body at rest ?
Q 16.
Do action-reaction forces produce the same magnitude of acceleration ?
Q 17.
Discuss briefly Galileo's ideas about motion.
Q 18.
State Newton’s second law of motion and establish that F = ma where symbols have their usual meanings.
Q 19.
It is difficult to balance our body when we accidentally slip on a peel of banana. Explain why?
Q 20.
Fill in the blanks :
On what factor does the inertia of a body depends? ____________
Q 21.
Fill in the blanks :
When a bus starts suddenly, the bus passengers standing in the bus tend to fall backwards. It is due to _______________.
Q 22.
Can every force produce motion in every object?
Q 23.
What are unbalanced forces?
Q 24.
What did Galileo conclude on the basis of his experiments on the motion of objects?
Q 25.
What is the SI unit of impulse.
Q 26.
What is the net momentum of gun and bullet system before firing?
Q 27.
What is the other name for Newton's first law of motion ?
Q 28.
In the above question, which body is damaged more ?
Q 29.
What is one newton force ?
Q 30.
What acceleration is produced by a force of 5 N acting on a body of mass 20 kg ?
Q 31.
State Newton's First Law of motion.
Q 32.
A body of mass 25 kg has momentum of 125 kg m/s. What is the velocity of the body?
Q 33.
While catching a fast moving ball, fielder gradually pulls his hand backwards. Give reasons.
Q 34.
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 35.
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.)
Q 36.
Fill in the blanks :
The study of motion of a body under the action of a force is called ______.
Q 37.
Fill in the blanks :
The momentum of an object is the product of its _____ and _______ and has the same direction as that of the ________.
Q 38.
Fill in the blanks :
Which has more inertia of Cricket ball or a rubber ball of the same size? __________
Q 39.
Fill in the blanks :
A cyclist on a levelled road does not come to rest immediately even he stops pedalling. It is due to ______________.
Q 40.
Fill in the blanks :
When the playing card is flicked with the finger the coin placed over it falls in the tumbler. It is due to ____________.
Q 41.
Force can change the shape and size of an object. Give an example.
Q 42.
What are balanced forces?
Q 43.
Which Newton's law is also known as the Law of Inertia?
Q 44.
Is force a scalar or vector quantity?
Q 45.
How is force related to acceleration produced in a body by its application?
Q 46.
Why mass is sometimes called coefficient of linear inertia?
Q 47.
When a force acting on a body has equal and opposite reaction, then why should the body move at all?
Q 48.
A constant force acts on an object of mass 5 kg for a duration of 2 s.It increases the object’s velocity from 3 m/s to 7 m/s.Find the magnitude of the applied force. Now if the force were applied for a duration of 5 s,what would be the final velocity of the object ?
Q 49.
Which would require a greater force : accelerating a 2 kg mass at 5
or a 4 kg mass at 2
?
Q 50.
A 150 g ball travelling at 30 m/s strikes the palm of a player’s hand and is stopped in 0 06 sec. Calculate the force exerted by the ball on the hand.
