Question:
Fill in the blanks :
On what factor does the inertia of a body depends? ____________
Force and Laws of Motion
Q 1.
A stone of 1 kg is thrown with a velocity if 20
across the frozen surface of a lake and comes to rest after travelling a distance of 50 m.What is the force of friction between the stone and the ice ?
Q 2.
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 3.
What would be the force required to produce an acceleration of 2
in a body of mass 12 kg ? What would be the acceleration if the force were doubled ?
Q 4.
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 5.
Can balanced forces move a body at rest ?
Q 6.
Do action-reaction forces act on the same body ?
Q 7.
Derive the relation F = ma,where the symbols have their usual meanings.
Q 8.
Fill in the blanks :
It is dangerous to jump out of a moving bus because due to _________ one falls forward.
Q 9.
A man pushes a box of mass 50 kg with a force of 80 N.What will be the acceleration of the box ? What would be the acceleration if the mass were halved ?
Q 10.
A body of mass 1 kg is kept at rest.A constant force of 6-0 N starts acting on it.Find the time taken by the body to move through a distance of 12 m.
Q 11.
A hockey ball of mass 200 g travelling at 10 m/s is struck by a hockey stick so as to return it along its original path with a velocity of 5 m/s.Calculate the change in momentum of the hockey ball by the force applied by the hockey stick.
Q 12.
Derive the unit of force using the second law of motion. A force of 5 N produces an acceleration of
on a mass
and an acceleration of 24
on a mass
.What acceleration would the same force provide if both the masses are tied together ?
Q 13.
What is the SI unit of force ?
Q 15.
Define momentum of a body.
Q 16.
State Newton's First Law of motion.
Q 17.
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 18.
Define 1 Newton force.
Q 19.
Which principle is involved in the working of a jet plane?
Q 20.
Which would require a greater force : accelerating a 2 kg mass at 5
or a 4 kg mass at 2
?
Q 21.
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 22.
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 23.
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 24.
What is the total momentum of the bullet and the gun on firing ?
Q 25.
A person in a bus tends to fall backwards, when it starts suddenly ?
Q 26.
Show that kg-
and N-s represent the same quantity.Which is that quantity ?
Q 27.
What is force ? What is inertia ? How is inertia measured ?
Q 28.
State and deduce the principle of conservation of momentum.
Q 29.
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 30.
State Newtons second law of motion.
Q 31.
Fill in the blanks :
An umbrella protects us from rain it is based on the property of _____________.
Q 32.
Fill in the blanks :
An athlete often jumps before taking a long jump. It is due to ________________.
Q 33.
Force can change the shape and size of an object. Give an example.
Q 34.
Which Newton's law is also known as the Law of Inertia?
Q 35.
Two hockey players of opposite teams,while trying to.hit a hockey ball on the ground collide and immediately become entangled.One has a mass of 60 kg,and was moving with a velocity 5.0 m/s,while the other has a mass of 55 kg and was moving faster with a velocity of 6.0 m/s towards the first player,In which direction and with what velocity will they move after they become entangled ? Assume that the frictional force acting between the feet of the two players and ground is negligible.
Q 36.
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 37.
What are balanced forces ?
Q 38.
What is the other name for Newton's first law of motion ?
Q 39.
What is the SI unit of momentum ?
Q 40.
Name the three types of inertia.
Q 41.
Name any two applications of the law of conservation of linear momentum.
Q 42.
Why does a gun recoil on firing ? Obtain an expression for recoil velocity of gun.
Q 43.
Explain briefly any three applications of Newton’s third law of motion.
Q 45.
What are balanced and unbalanced forces?
Q 46.
If the set of forces acting on an object are balanced, then object
(a) must be at rest.
(b) must be moving
(c) must not be accelerating.
(d) none of these.
Q 47.
What are non-contact forces? Give examples.
Q 48.
Define 1N (Newton).
Q 49.
An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 ms-2.
Q 50.
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?
