1. Define the term “force” and state the effects of force.
2. What do youunderstand by the term “balanced forces and
“unbalanced forces” .Explain with examples?
3. State the first law of motion . Give two examples to
illustrate Newton’s first law of motion.
4. What do you mean by inertia .How is it related to mass?
5. Give reason for the following
a)A person travelling in moving bus tend to fall forward
when it breaks and he tend to fall backwards when the bus
accelerates from rest
b) When a hanging carpet is beaten withnstick, the dust
particles start coming out of it ?
c) When a tree is shaken ,its fruits and leaves fall down.
d) It is dangerous to jump out of a moving bus .
e) Vehicles are provided with seat belts ?
6. Define momentum of a body. On what factors does the
momentum of the body depends ?
7. A man throws a ball weighing 500g vertically upwards with a
speed of 10 m/s.
a) What will be its initial momentum ?
b) What would be its momentum at the highest point of
its flight ?
8. What is the momentum of a man of mass 75 kg when
he walks with a unform velocity of 2m/s ?
9.What is the change in momentum of a car weighing
1500kg when its speed increases from 36km/h to 72km/h
uniformly?
10. Athelets in pole jump event falls on a cushioned surface
not on a floor. Why ?
11. State the Second law of motion.Using the second law of
motion, derive the relation between force and accelaration.
12. Give reason and the law related to the following statement.
“ it is difficult for the fireman to hold the hose ejecting a
large amount of water.”
13. State reason for the following
a) Road accidents at high speed is worse than the
accidents at low speed.
b) When a motor car takes a sharp turn at a high speed,
the passengers are thrown to one side.
c) The fielders lowers his hands while catching a fast
moving cricket ball .
d) While swimming a person pushes the water
backward.
e) A gun recoils on firing
14. A body of mass 5kg is acted upon by a force of 1 N , what
would be the acceleration caused ?
15. Calculate the force required to change the velocity of a car
from 20 m/s to 36 m/s in 8 s. The mass of the car is 1500 kg .
16. State the principle on which a rocket works.
15.State the law of conservation. Mathematically derive the
Law of conservation of momentum.
17. Two objects of masses 100g and 200g moving along the
same straight linbe and direction with velocities 2m/s and
3m/s. After collision,the first object moves with a velocity
3m/s, then find the velocity of the second.
18. The speed time graph of a car is given as follows. The car
weighs 100kg.
a) What is the distance travelled by the car the first two
seconds.
b) What is the breaking force applied at the end of 5 sec to
bring the car to stop within one second?
19. A bullet of mass 10 g moving with a velocity of 400m/s gets
embedded in a freely suspended wooden block of mass 900g.
What is the velocity acquired by the block ?
20. A gun of mass 3 kg fires a bullet of mass 30 g . The bullet
takes 0.003 s to move through the barrel of the gun and
acquires a velocity of 100 m/s.Calculate
i) the velocity with which the gun recoils
ii) The force exerted on the gun due to the recoil of the gun.
21. State Newtons third law of motion and give two examples
to illustrate the law.
Answers
Answer:
1. A force acting on an object causes the object to change its shape or size, to start moving, to stop moving, to accelerate or decelerate. When there's the interaction between two objects they exert a force on each other, these exerted forces are equal in size but opposite in direction.
2. BALANCED FORCE: When two forces of equal magnitude but acting in opposite directions on an object. UNBALANCED FORCE: When two forces of unequal magnitudes acting in opposite directions on an object. EX:A bicycle will slow down if the rider stop pedalling it.
Explanation:
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Answer:
The effective mass tensor diverges (becomes infinite) for linear dispersion relations, such as with photons or electrons in graphene. (These particles are sometimes said to be massless, however this refers to their having zero rest mass; rest mass is a distinct concept from effective mass.)