SAT Physics - Force

Exam Duration: 45 Mins Total Questions : 30

1 )

Graphite powder is used in machines to

(a)
enhance friction
(b)
reduce friction
(c)
enhance profit
(d)
reduce efficiency

2 )

When an object undergoes acceleration

(a)
its speed always increases
(b)
it always falls towards the earth
(c)
force always acts on it
(d)
its velocity always increases

3 )

The buoyant force depends on the

(a)
density of a liquid
(b)
depth of a liquid
(c)
colour of a liquid
(d)
none ofthese

4 )

A piece of wood floats in water. What happens to it in alcohol?

(a)
sinks
(b)
floats higher
(c)
sinks and rises
(d)
stays as before

5 )

The momentum of a heavy object at rest will be

(a)
large
(b)
infinity
(c)
zero
(d)
small

6 )

A gun of mass 1000 kg fires a shell of mass 2 kg with a velocity of 200 m/s. calculate the velocity of recoil of the gun

(a)
0.2 m/s
(b)
4 m/s
(c)
0.4 m/s
(d)
2 m/s

7 )

Clouds float in the atmosphere because of their low

(a)
force
(b)
density
(c)
pressure
(d)
velocity

8 )

Which of the following physical quantity has no unit?

(a)
density
(b)
pressure
(c)
relative density
(d)
thrust

9 )

A single horizontal force F is applied to a block of mass M₁which is in contact with another block of mass M₂. If the surfaces are frictionless. The force between the blocks is

(a)
\(\frac { { M }_{ 1 }F }{ { M }_{ 2 } } \)
(b)
\(\frac { { M }_{ 1 }{ M }_{ 2 }g }{ { M }_{ 1 }+{ M }_{ 2 } } \)
(c)
\(\frac { { M }_{ 2 }F }{ { M }_{ 1 }+{ M }_{ 2 } } \)
(d)
\(\frac { { M }_{ 1 }+{ M }_{ 2 } }{ { M }_{ 1 }F } \)

10 )

A body of mass 2 kg undergoes a change in speed from 50 to 0.50 m/s. The momentum of the body would

(a)
increase by 101 kg m/s
(b)
increase by 99 kg m/s
(c)
decrease by 101 kg m/s
(d)
decrease by 99 kg m/s

11 )

A bullet of mass M₁ and velocity V is fired into a block of wood of mass M₂. If loss of any mass and friction be neglected, the velocity of the system must be

(a)
\(\frac { { M }_{ 1 }V }{ { M }_{ 1 }+{ M }_{ 2 } } \)
(b)
\(\frac { { M }_{ 1 }+{ M }_{ 2 } }{ { M }_{ 1 }V } \)
(c)
\(\frac { { M }_{ 1 }+{ M }_{ 2 } }{ { M }_{ 2 }V } \)
(d)
\(\frac { { M }_{ 1 }+V }{ { M }_{ 1 }{ M }_{ 2 } } \)

12 )

In a pressure cooker, the food cooks faster because

(a)
increased pressure lowers the boiling point of water
(b)
decreased pressure raises the boiling point of water
(c)
increased pressure raises, the boiling point of water
(d)
decreased pressure lowers the boiling point of water

13 )

In collision in which the direction of motion of bodies make an angle with each other, then for this system

(a)
only magnitude of momentum is conserved
(b)
only direction of momentum is conserved
(c)
Both magnitude and direction of momentum is conserved
(d)
Momentum depends on nature of the body

14 )

The sparks produced during sharpening of a knife against a grinding wheel leaves the rim of the wheel tangentially. This is due to_________

(a)
Inertia of rest
(b)
Inertia of motion
(c)
Inertia of direction
(d)
Force applied

15 )

1 Newton = _______

(a)
1 Kg m/s
(b)
1 Kg m/s²
(c)
1 Kg² m²/s²
(d)
1g

16 )

The resultant of action and reaction forces is ________

(a)
Greater than zero
(b)
Less than zero
(c)
Zero
(d)
None of the above

17 )

What is a difference between an object's speed and velocity?

(a)
Speed includes direction as well as the rate of travel
(b)
Velocity includes time during which travel occurs
(c)
Velocity includes the direction of travel whereas speed does no
(d)
There is no difference

18 )

Which of the following statements correctly states Newton's first law of motion?

(a)
Every object retains its state of rest or its state of accelerated straight-line motion unless acted upon by an unbalanced force
(b)
Every object retains its state of rest or its state of uniform straight-line motion unless acted upon by a balanced force
(c)
Every object retains its state of rest or its state of uniform straight-line motion unless acted upon by an unbalanced force
(d)
None of the above is correct

19 )

A person walking on a level surface moves forward because the forces of

(a)
His feet pushing forward on the ground
(b)
His feet pushing backward on the ground
(c)
The ground pushing forward on his feet
(d)
The ground pushing backward on his feet

20 )

The table below shows the length of a wire as the load on it is increased

load/N	0	10	20	30
length/cm	50.0	52.1	54.1	56.3

Which graph correctly shows the extension of the wire plotted against load?

21 )

The propeller on a boat pushes water backwards with a force of 2000 N. The boat moves through the water against a total resistive force of 1800 N.

According to Newton's third law, what is the forward force on the propeller due to the water?

(a)
3800 N
(b)
2000 N
(c)
1800 N
(d)
200 N

22 )

A steel spring is stretched by a load. The load is increased.
At first the extension is proportional to the load. The spring reaches its limit of proportionality at L.
Which is the correct graph of the extension against load for the spring?

23 )

Forces are applied to a uniform beam pivoted at its centre. Which beam is balanced?

24 )

The force of freely falling body is directly proportional to

(a)
mass of body
(b)
acceleration of body
(c)
velocity of body
(d)
both (A) and (B)

25 )

When you kick a stone, you get hurt. Due to which property this happens?

(a)
inertia of stone
(b)
velocity of the kick
(c)
momentum of the kick
(d)
reaction of the stone

26 )

A motor bike accelerates on the horizontal road due to the force exerted by:

(a)
the engine of motorbike
(b)
the earth
(c)
the driver on the motorbike
(d)
none of the above.

27 )

A vehicle has a mass of 1500 kg. If the vehicle is to be stopped with a negative acceleration of 1.7 ms², the force of friction between the vehicle and road is: