Forces and Laws of Motion Test

Result

Forces and Laws of Motion Test - 34

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

Two bodies of masses 1m and 4m have the same KE. What is the ratio of their momenta?

A
2:1

B
1:2

C
1:4

D
4:1

Solution

The relation between kinetic energy $$(K)$$ and momentum $$(p)$$ is given by, $$K=\dfrac{p^2}{2m}$$ where $$m$$ be the mass of the body
So, $$p=\sqrt{2mK}$$
Hence, $$\dfrac{p_1}{p_2}=\dfrac{\sqrt{2(m)K_1}}{\sqrt{2(4m)K_2}}=\sqrt{(1/4)}=2/1$$ as they have same kinetic energies so $$K_1/K_2=1$$
Question 2
1 / -0

A 10 N force applied on a body produces in it an acceleration of $$2 \,m\, s^{-2}$$, then the mass of the body is ______.

A
10 kg

B
2 kg

C
5 kg

D
6 kg

Solution

$$F=10N$$
$$a=2m/s^{2}$$
By newton second law
$$F=ma$$
$$10=2M$$
$$M=5Kg$$
Question 3
1 / -0

Which of the following safety features are used in vehicles to reduce the negative effects of inertia?
(i)Safety seat belts
(ii)Automatic air bags
(iii)Absorber bumpers

A
Only (i) and (ii)

B
Only (ii) and (iii)

C
Only (i) and (iii)

D
(i), (ii) and (iii)

Solution

$$Force=mass \times \dfrac{momentum}{time}$$
since the effect of inertia depend on force if the time of impact is increased and hence the same force will produce less effect of inertia the safety seat belt,automatic air bag,Absorber bumpers produce the same effect to decrease the negative effect of inertia.
Question 4
1 / -0

A man weighing 60 kg is walking with a uniform velocity of 4 m $$s^{-1}$$. Calculate the momentum of a man.

A
120 m $$s^{-1}$$

B
240 m $$s^{-1}$$

C
360 m $$s^{-1}$$

D
480 m $$s^{-1}$$

Solution

Given,
$$m=60\ kg\\v=4\ m/s$$
Momentum = mass $$\times$$ velocity.
Momentum of man $$p=m\times v=60\times 4=240\ kg m/s$$
Question 5
1 / -0

Identify the type of force in diagram

A
Push

B
Pull

C
No force is acting

D
Both A and B

Solution

When a force is exerted in such a way that movement caused is towards oneself, such type of force is pull.
Question 6
1 / -0

A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is

A
constant and equal to mg in magnitude

B
constant and greater than mg in magnitude.

C
variable but always greater than mg

D
at first greater than $$mg$$, and later becomes equal to $$mg$$.

Solution

When the man gets straight up and stand in this process initially for the man to move upward he needs a net external force in the upward direction which can only be provided by the normal reaction($$N$$) from the ground.
Therefore, $$N-mg>0\quad \Rightarrow N>mg$$ (initially)
and later when he stands up and becomes static then $$N=mg$$
Question 7
1 / -0

On a stationary sail boat, air is blown from a fan attached to the boat. The boat

A
moves in opposite direction in which the air is blown

B
does not move

C
moves in the same direction in which air blows

D
spins around

Solution

In this case air blown by the fan will try to push the sail boat in a certain direction.But at the same time due to Newton's third law of motion the fan will experience a force due to the air blown in a direction opposite to the direction in which the sail boat will experience the force due to the blown air.So, as a whole the system will be at rest and it will not move
Question 8
1 / -0

If set of forces acting on a body are balanced, the body

A
must be moving

B
must be at rest

C
must not be revolving

D
must not be accelerating

Solution

If there is a balanced force, the object will remain in its present state, i.e., if it is moving, it will keep on moving with uniform speed. If it is at rest, it will remain at rest.
Question 9
1 / -0

When a bus suddenly takes a turn, the passengers are thrown outwards because of

A
Inertia of motion

B
Acceleration of motion

C
Speed of motion

D
Both (b) and (c)

Solution

According to the law of inertia of motion, a body will continue moving with constant velocity unless any force acts on it. When a bus is moving straight the passengers inside are also moving straight but when suddenly bus turn left passengers still continue to move straight because no force is acting on passengers so they will move with same magnitude and direction i.e. outwards when bus turns .
Question 10
1 / -0

What causes a moving body to resist a change in its state of motion?

A
Its acceleration

B
Its speed

C
Its inertia

D
Its weight

Solution

The property of a body by virtue of which it resists any change in its state of rest or of motion in a straight line on its own is called its inertia.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Forces and Laws of Motion Test - 34

Result

Forces and Laws of Motion Test - 34

Score

-

Rank

-

SHARING IS CARING

Question 1

2:1

1:2

1:4

4:1

Solution

Question 2

10 kg

2 kg

5 kg

6 kg

Solution

Question 3

Only (i) and (ii)

Only (ii) and (iii)

Only (i) and (iii)

(i), (ii) and (iii)

Solution

Question 4

120 m $$s^{-1}$$

240 m $$s^{-1}$$

360 m $$s^{-1}$$

480 m $$s^{-1}$$

Solution

Question 5

Push

Pull

No force is acting

Both A and B

Solution

Question 6

constant and equal to mg in magnitude

constant and greater than mg in magnitude.

variable but always greater than mg

at first greater than $$mg$$, and later becomes equal to $$mg$$.

Solution

Question 7

moves in opposite direction in which the air is blown

does not move

moves in the same direction in which air blows

spins around

Solution

Question 8

must be moving

must be at rest

must not be revolving

must not be accelerating

Solution

Question 9

Inertia of motion

Acceleration of motion

Speed of motion

Both (b) and (c)

Solution

Question 10

Its acceleration

Its speed

Its inertia

Its weight

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.