( kg ms⁻¹, centripetal, same, 1000, velocity, newton, mass, force, momentum, masses, 10⁵, spring, 9.8 x 10⁵, centre)
1) Force produces an acceleration in the_____ direction as the force.
2) Inertia is directly proportional to the_____ of the body.
3) Force of 1 newton produces an acceleration of ____ ms⁻² in a mass of 1 g.
4) The SI unit of weight is_____.
5) The SI unit of momentum is _____.
6) Force = Rate of change of _____.
7) Weight of a body is measured by a _____ balance.
8) When a shot is fired from a gun, the velocity of the gun and bullet are inversely proportional to their ______.
9) The weight of a body is zero at the _____ of the earth.
10) The acceleration towards the centre in circular motion is called the__ acceleration.
11) One newton= _____ dyne.
12) Momentum = mass x ______.
13) 1 kgf _____ dyne.
14) The acceleration produced in a body is directly proportional to the____ applied on it.
B) State whether true or false
1) When an object undergoes an acceleration, a force always acts on it.
2) The mass of a body cannot be zero.
3) To every action there is an equal and opposite reaction.
4) The mass of a body is constant for a body at ordinary speed.
5) A body can have weight but no mass.
6) The weight of a body changes from place to place.
7) The momentum of a body depends on its mass and the velocity.
8) The force of gravity acts vertically upwards at the centre of gravity of a body.
9) The moment of a body is the product of the mass of the body and acceleration.m.
10) The weight of an object on the moon is about one-fifth of its weight on the earth.
11) It is difficult to stop a tennis ball than a cricket ball moving with the same speed.
C) Very Short Questions:
1) What law of motion gives us the mathematical measurement of force ?
2) Is a force needed to keep a body moving with uniform velocity?
3) Write SI unit of
a) mass.
b) force.
4) What is the relation between SI and CGS units of force?
5) State the SI and CGS units of mass. How are these units related ?
6) Write an expression for the momentum of a body.
7) Give its SI and CGS units of force.
8) Define the term 'linear momentum ' Give its SI unit.
9) Is momentum a scalar or a vector quantity ?
10) On what factor does the inertia of a body depend ?
11) What is the relation between kilogramme force and newton ?
12) State the relation between force, mass and acceleration.
13) State the SI and CGS units of weight.
14) Name the physical quanty whose unity is kg ms⁻¹.
15) Name the physical quantity whose unit is newton.
16) How is the weight of a body related to its mass?
17) State the relation between the momentum of a body and the force acting on it.
18) On what factor does the momentum of a body depend ?
19) What is the total moment of the bullet and the gun before firing ?
20) What name is given to the product of mass and velocity of a body ?
21) Which physical quantity corresponds to the rate of change of momentum?
22) A force is applied on
i) a non rigid object and
ii) a rigid object.
How does the effect of the force differ in both cases?
23) State the SI unit of momentum of a body.
D) Short Answer Type Questions:
1) Will a body weight more in air or in vacuum when weighed with a spring balance ? Give a reason for your answer.
2) Bodies of larger mass need greater initial effort to put them in motion. Why ?
3) Give the magnitude and direction of the net force acting on:
a) a drop of rain falling down with a constant speed.
b) a cork of mass 10g floating on water.
c) A kite skillfully held stationery in the sky.
d) A car moving with a constant velocity of 30 km h⁻¹ on a rough road.
4) Derive a relation between SI and CGS unit of force.
E) Multiple Choice Questions
1) When a freely moving object of mass 1 kg is subjected to a force of 1N, it moves with:
a) a speed of 1 ms⁻¹
b) a peed of 1 kms⁻¹
c) an acceleration of 1 ms⁻²
d) an acceleration of 10 ms⁻²
2) When a net force acts on an object, it will be accelerated in the direction of the force with an acceleration proportional to
a) the force on the object.
b) the velocity of the object.
c) the mass of the object.
d) the Inertia of the object.
3) a force:
a) cannot start or stop the motion of a body.
b) can change the speed or direction of motion or both of a moving body.
c) cannot bring a change in dimensions of a body
d) none
4) When an object undergoes an acceleration:
a) its velocity always increases.
b) its speed always increases.
c) it always falls towards the Earth.
d) a force always acts on it.
5) The force required to produce an acceleration of 5 ms⁻¹ in an object of mass 2 kg is:
a) 2.5N b)?10.0N c) 0.4 N d) 7.0 N
6) 1N is the force which produces.
a) an acceleration of 1ms⁻² in a body of mass 1 g.
b) an acceleration of 1cms⁻² in a body of mass 1kg.
c) an acceleration of 1cms⁻² in a body of mass 1kg.
d) an acceleration of ms⁻² in a body of mass 1kg.
7) The correct relationship between the force, mass and acceleration is:
a) F= a/m b) F= ma² c) F= ma d) F= m/a
8) External force acting on an object:
a) are always balanced
b) are always unbalanced
c) may or may not be balanced. d) none
9) a body X has a mass of 30 kg and is moving with the velocity of 10 ms⁻¹. Another body Y has a double mass but half of the velocity. The momentum are in the ratio of
a) 1:2 b) 1 : 1 c) 1:4 d) 2:1
10) The rate of change of momentum gives :
a) moment b) impulse c) force d) acceleration
11) Mass is given by the relation
a) velocity/acceleration
b) force/velocity
c) force.acceleration
d) distance/velocity
12) The momentum of a heavy at rest will be :
a) large b) small c) zero d) none
13) The SI unit of momentum is:
a) dyne b) newton c)!kg ms⁻¹ d) cms⁻²
14) The momentum of a toy car of mass 400 g moving with a speed of 5 ms⁻¹ is:
a) 1 mg ms⁻¹ b) 2kgms⁻¹ c) 10kg ms⁻¹ d) 5 kg ms⁻¹
15) If the mass of a body is m kg, its weight will be:
a) m g b) mg N c) m dyne d) none
16) If the mass of a body and the force acting on it are both doubled :
a) its acceleration will become double
b) there will be no change in its acceleration.
c) its acceleration will become half
d) none
17) 1 kg weight is equals to:
a) 9.8N b) 98 c) 980 N d) 9.8 dyne
18) The weight of an object:
a) refers to its inertia
b) is the force with which it is attracted by the earth.
c) is the gravity of matter it contains.
d) none
19) An object undergoes an acceleration of 8ms⁻¹ starting from rest. The distance travelled in 1 second is:
a) 2m b) 4m c) 6m d) 8m
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