Question:
What is the net momentum of gun and bullet system before firing?
Answer:
The net momentum of gun and bullet system before firing is zero, as velocities of both (gun and bullet) are zero.
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.
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 28.
What is the other name for Newton's first law of motion ?
Q 29.
In the above question, which body is damaged more ?
Q 30.
What is one newton force ?
Q 31.
What acceleration is produced by a force of 5 N acting on a body of mass 20 kg ?
Q 33.
State Newton's First Law of motion.
Q 34.
A body of mass 25 kg has momentum of 125 kg m/s. What is the velocity of the body?
Q 35.
While catching a fast moving ball, fielder gradually pulls his hand backwards. Give reasons.
Q 36.
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 37.
Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
Q 38.
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 39.
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 40.
Fill in the blanks :
The study of motion of a body under the action of a force is called ______.
Q 41.
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 42.
Fill in the blanks :
Which has more inertia of Cricket ball or a rubber ball of the same size? __________
Q 43.
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 44.
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 45.
Force can change the shape and size of an object. Give an example.
Q 46.
What are balanced forces?
Q 47.
Which Newton's law is also known as the Law of Inertia?
Q 48.
A person standing in a moving bus falls forward if driver applies brakes suddenly. Name the inertia applying resistance here?
Q 49.
Why do we tend to fall outwards when a car takes a steep turn?
Q 50.
Is force a scalar or vector quantity?
