Newton's second law

Q.

The distance travelled by a moving body is directly proportional to time. Is any external force acting on it?

Q.

A car moving with a velocity of $10m{s}^{-1}$ can be stopped by the application of constant force $F$ in a distance of $20m$. If the velocity of the car is $30m{s}^{-1}$, it can be stopped by this force in

1. $\frac{20}{3}m$

2. $20m$

3. $60m$

4. $180m$

Q. A force of $20N$ acting on a body of mass $10kg$ is found to double its velocity in $8s$. Find its initial velocity.

1. $4m{s}^{-1}$
2. $8m{s}^{-1}$
3. $32m{s}^{-1}$
4. $16m{s}^{-1}$

Q.

A car is moving with a uniform velocity of 30 m $s^{-1}$. It is stopped in 2 s by applying a force of 1500 N through its brakes. Calculate:

(a) the change in momentum of car,
(b) the retardation produced in car and
(c) the mass of the car.

Q.

What relation between force and momentum can be used to solve this problem?
"An object of mass 100 Kg is accelerated uniformly from a velocity of 5 m/s to 8 m/s in 6 seconds. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object."

1. The rate of change of momentum of an object is directly proportional to the resultant force applied.

2. The rate of change of momentum of an object is inversely proportional to the resultant force applied.

3. Change in momentum of an object is inversely proportional to the resultant force applied.

4. Change in momentum of an object is directly proportional to the resultant force applied.

Q. The force required to produce an acceleration of 1 m/s² on a body of mass 1 kg is

1. 1 Newton
2. 10 Newton
3. cannot be determined
4. 9.8 N

Q.

A force acting on a body produces a constant acceleration. The equation written is as follows:

$F=Km\times \frac{(V-U)}{t}$

F- Force; K-constant;

m- mass; V- final velocity

U- initial velocity; t- time taken

a- acceleration; P- momentum

The equation can also be written as___ .

1. F = m*p/t

2. F = m*p

3. F = m*a

4. F = 2 m*a

Q.

A force $F_1$ acting on a body of $2\mathrm{kg}$ produces an acceleration of $2.5\mathrm{m}/{\sec }^2$. An other force $F_2$ acting on the another body of mass $5\mathrm{kg}$ produces an acceleration of $2\mathrm{m}/{\sec }^2$. Find the ratio of $F_1/F_2$.

1. $2:1$

2. $4:1$

3. $1:2$

4. $1:8$

Q.

A car of mass $500kg$ is accelerating at $2m{s}^{-2}$. What is the net force acting on the car?

1. $500N$
2. $250N$
3. $1000N$
4. $1500N$

Q. Mass times rate of change in velocity is ___

1. displacement
2. acceleration
3. force
4. momentum

Q. An object moves with an acceleration of $3m{s}^{-2}$ when a force of 30 N is applied. The mass of the body is ___ kg.

1. 15
2. 30
3. 60
4. 10

Q.

Two objects moving along the same straight line are leaving point A with an accelerations $a$ and $2a$, and velocities $2u$ and $u$ respectively at time $t=0$. The distance moved by the objects with respect to point A when one object overtakes the other is

Q. A ball starts to roll over a horizontal surface with an initial velocity of $0.5m/s$. Due to friction, it stopped after 10 seconds. Calculate the acceleration of the ball.

1. $0.5m/s^2$
2. $0.05m/s^2$
3. $-0.5m/s^2$
4. $-0.05m/s^2$

Q.

What is the magnitude of force needed to produce an acceleration of $4{ms}^{-2}$​ in a ball of $6kg$?

1. $20N$

2. $26N$

3. $30N$

4. $24N$

Q. A person of mass $60\text{kg}$ is in a lift. The change in the apparent weight of the person, when the lift accelerates up with an acceleration of $2{\text{m/s}}^2$ and then down with an acceleration of $2{\text{m/s}}^2$ is

1. $120\text{N}$
2. $240\text{N}$
3. $480\text{N}$
4. $720\text{N}$

Q. A person of mass $60\text{kg}$ is in a lift. Calculate the change in the apparent weight of the person, when the lift accelerates up with an acceleration of $2{\text{m/s}}^2$ and then down with an acceleration of $2{\text{m/s}}^2$ is

Q. How does the acceleration ($a$) produced by a given force ($F$) depend on mass ($m$) of the body?

1. $F=\frac{m}{g}$
2. $F=mg$
3. $F=ma$
4. $F=\frac{m}{a}$

Q. A person of mass $60\text{kg}$ is in a lift. Calculate the change in the apparent weight of the person, when the lift accelerates up with an acceleration of $2{\text{m/s}}^2$ and then down with an acceleration of $2{\text{m/s}}^2$ is

Q.

A car of mass $500kg$ is accelerating at $2m{s}^{-2}$. What is the net force acting on the car?

1. $500N$
2. $250N$
3. $1000N$
4. $1500N$

Q. An object moves with an acceleration of $3m{s}^{-2}$ when a force of $30N$ is applied. The mass of the body is ___.

1. $90kg$
2. $10kg$
3. $50kg$
4. $40kg$

Q. Calculate the force required to accelerate a car from rest to a velocity of $30m{s}^{-1}$ in $10seconds$. The mass of the car is $1500kg$.

1. $4000N$
2. $3000N$
3. $4500N$
4. $3500N$

Q. The acceleration produced in a body by a force of given magnitude depends on:

1. mass of the body
2. size of the body
3. shape of the body
4. none of these

Q. A car of mass $\text{1000 kg}$ moving with a velocity of $\text{20 m/s}$ is brought to rest by applying brakes in $\text{10 seconds}$. What is the force applied by the brakes?

1. $\text{1000 N}$
2. $\text{2000 N}$
3. $\text{4000 N}$
4. $\text{10000 N}$

Q.

____ is the force when acting on the body of mass _____ produces an acceleration of $1m{s}^{-2}$.

Q. An object moves with an acceleration of 3 ${ms}^{-2}$ when a force of 30 N is applied. The mass of the body is ___ kg.

1. 30
2. 10
3. 15
4. 60

Q. A force $\overrightarrow{F}=6t^2\hat{i}+4t\hat{j}$ is acting on a particle of mass $3kg$ then what will be velocity of particle at $t=3$ second and if at $t=0$, particle is at rest :

1. $18\hat{i}+6\hat{j}$
2. $18\hat{i}+12\hat{j}$
3. $12\hat{i}+6\hat{j}$
4. None of these

Q.

Calculate the force required to accelerate a car from rest to a velocity of $30m{s}^{-1}$ in $10$ seconds. The mass of the car is $1500kg$.

1. $4000N$

2. $3500N$

3. $3000N$

4. $4500N$

Q. A force $2\hat{i}+\hat{j}+\hat{k}$ newtons acts on a body which is initially at rest. lf the velocity of the body at the end of 20 seconds is $4\hat{i}+2\hat{j}+2\hat{k}{ms}^{-1}$, the mass of the body

1. 20 kg
2. 15 kg
3. 5 kg
4. 10 kg

Q.

While an athlete is running at a constant acceleration of $4.5m{s}^{-2}$, he exerts a force of $300N$. What is the mass of the athlete?

1. $64kg$

2. $69.6kg$

3. $65kg$

4. $66.67kg$

Q. Calculate the force required to accelerate a car from rest to a velocity of $30m{s}^{-1}$ in $10seconds$. The mass of the car is $1500kg$.

1. $4000N$
2. $3000N$
3. $4500N$
4. $3500N$