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Question 1. Which of the following has more
inertia:
(a) a rubber ball and a
stone of the same size?
(b) a
bicycle and a train?
(c) a fiverupees
coin and a one-rupee coin?
Question 2. In the following example, try to
identify the number of times the
velocity of the ball changes:
“A football player kicks a football
to another player of his team who
kicks the football towards the
goal. The goalkeeper of the
opposite team collects the football
and kicks it towards a player of
his own team”.
Also identify the agent supplying
the force in each case.
Question 3. Explain why some of the leaves
may get detached from a tree if
we vigorously shake its branch.
Question 4. Why do you fall in the forward
direction when a moving bus
brakes to a stop and fall
backwards when it accelerates
from rest?
Question 1. If action is always equal to the
reaction, explain how a horse can
pull a cart.
Question 2. Explain, why is it difficult for a
fireman to hold a hose, which
ejects large amounts of water at
a high velocity.
Question 3. From a rifle of mass 4 kg, a bullet
of mass 50 g is fired with an
initial velocity of 35 m s–1.
Calculate the initial recoil velocity
of the rifle.
Question 4. Two objects of masses 100 g and
200 g are moving along the same
line and direction with velocities
of 2 m s–1 and 1 m s–1, respectively.
They collide and after the collision,
the first object moves at a velocity
of 1.67 m s–1. Determine the
velocity of the second object.
Question 1. 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.
Question 2. When a carpet is beaten with a stick, dust comes out of it.
Explain.
Question 3. Why is it advised to tie any luggage kept on the roof of a bus
with a rope?
Question 4. A batsman hits a cricket ball which then rolls on a level ground.
After covering a short distance, the ball comes to rest. The ball
slows to a stop because
(a) the batsman did not hit the ball hard enough.
(b) velocity is proportional to the force exerted on the ball.
(c) there is a force on the ball opposing the motion.
(d) there is no unbalanced force on the ball, so the ball would
want to come to rest.
Question 5. 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.)
Question 6. A stone of 1 kg is thrown with a velocity of 20 m s–1 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?
Question 7. A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg,
along a horizontal track. If the engine exerts a force of 40000 N
and the track offers a friction force of 5000 N, then calculate:
(a) the net accelerating force
(b) the acceleration of the train
(c) the force of wagon 1 on wagon 2.
Question 8. 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 m s–2?
Question 9. What is the momentum of an object of mass m, moving with a
velocity v?
(a) (mv)2
(b) mv2
(c) ½ mv2
(d) mv
Question 10. 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?
Question 11. Two objects, each of mass 1.5 kg, are moving in the same
straight line but in opposite directions. The velocity of each
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