Question:
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
Answer:
Here,mass of one object, = kg=kg
mass of second object,=200 kg=kg=kg
Initial velocity of 1st object,=2 m/s ; Initial velocity of 2nd object.= 1 m/s
Final velocity of 1st object = 1.67 m/s ;Final velocity of 2nd object,= ?
According to principle of conservation of linear momentum,
+ =+ or x1.67+v2=x2+x1=
v2=-=orx5==1.17 m/s.
Force and Laws of Motion
Q 1.
What is the total momentum of a bullet and a gun before firing?
Q 2.
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 3.
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 4.
Using second law of motion, derive the relation between force and acceleration.
Q 5.
Are action-reaction forces simultaneous ?
Q 6.
Do action-reaction forces produce the same magnitude of acceleration ?
Q 8.
Define momentum of a body.
Q 9.
State Law of conservation of momentum.
Q 10.
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 11.
Fill in the blanks :
The study of motion of a body under the action of a force is called ______.
Q 12.
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 13.
Give an example that force can make a stationary body move.
Q 14.
What is the net momentum of gun and bullet system before firing?
Q 15.
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 16.
For how long should a force of 100 N act on a body of mass 20 kg so that it acquires a velocity of 100 m/s ?
Q 17.
A bullet of mass 50 g is fired from a gun of mass 6 kg with a velocity of 400 m/s.Calculate the recoil velocity of the gun.
Q 18.
Is momentum a scalar or vector ?
Q 19.
Discuss briefly Galileo's ideas about motion.
Q 20.
What's the relation between 1N and 1 dyne?
Q 21.
When two objects act on each other, does action-reaction force pair cancel out each other?
Q 22.
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 23.
It is difficult to balance our body when we accidentally slip on a peel of banana. Explain why?
Q 24.
Law of conservation of momentum is applicable to an isolated system. What do you mean by an isolated system?
Q 25.
A bullet of mass 10 g 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. Also calculate the magnitude of the force exerted by the wooden block on the bullet.
Q 26.
The speed-time graph of a car is shown below. The car weighs 1000kg.
(i) Find the distance covered by the in fits two seconds.
(ii) Find how much force is applied by the car brakes in the fifth second so that the car comes to an halt by sixth second.
Q 27.
Fill in the blanks :
When a car enters a curved path, the person sitting in it is thrown outwards. This is because of the property of ______________.
Q 28.
Fill in the blanks :
Which has more inertia of Cricket ball or a rubber ball of the same size? __________
Q 29.
Fill in the blanks :
________ is a measure of intertia.
Q 30.
Can balanced forces change the shape and size of an object?
Q 31.
Can every force produce motion in every object?
Q 32.
A person standing in a moving bus falls forward if driver applies brakes suddenly. Name the inertia applying resistance here?
Q 33.
Define force of friction.
Q 34.
A motorcar is moving with a velocity of 108 km/h and it takes 4 second to stop after the brakes are applied.Calculate the force exerted by the brakes on the motorcar if its mass alongwith the passengers is 1000 kg.
Q 35.
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 36.
What is the SI unit of force ?
Q 37.
Can balanced forces move a body at rest ?
Q 38.
Can balanced forces change the shape and size of a body ?
Q 39.
On what factor does inertia of a body depend ?
Q 40.
The masses of two objects are 2 kg and 20 kg. Which has greater inertia ?
Q 41.
What is the SI unit of momentum ?
Q 42.
What is the total momentum of the bullet and the gun on firing ?
Q 43.
In the above question, which body is damaged more ?
Q 44.
Name the various effects of force.
Q 45.
What is one newton force ?
Q 46.
Name any two applications of the law of conservation of linear momentum.
Q 47.
Show that kg-
and N-s represent the same quantity.Which is that quantity ?
Q 48.
Give atleast four applications of Newton’s second law of motion.
Q 49.
Is force required to keep a moving object in motion (yes/no)?
Q 50.
A body of mass 25 kg has momentum of 125 kg m/s. What is the velocity of the body?
