Average acceleration

Q. Statement I: Retardation is directed opposite to the velocity.
Statement II: Retardation is equal to the time rate of decrease of velocity.

1. Both statement 1 and statement 2 are correct and statement 2 is the correct explanation of statement 1.
2. Both statement 1 and statement 2 are correct and statement 2 is not the correct explanation of statement 1.
3. Statement 1 is correct and statement 2 is incorrect.
4. Statement 1 is incorrect and statement 2 is correct.

Q.

The table below shows the data for a car stopping on a wet road.

What is the approximate stopping distance for a car traveling $35$ mph?

v(mph)	distance(ft)
$15$	$17.9$
$20$	$31.8$
$50$	$198.7$

Q. A scooter travelling at $10\text{m/s}$ speed up to $20\text{m/s}$ in $4\text{sec}$. Find the average acceleration of scooter.

1. $5{\text{m/s}}^2$
2. $2.5{\text{m/s}}^2$
3. $2{\text{m/s}}^2$
4. $4{\text{m/s}}^2$

Q.

A Porsche can go from $0\text{km/hr}$ to $100\text{km/hr}$ in $10\text{s}$. What is its average acceleration?

1. $2.77\text{m}/s^2$

2. $3.66\text{m}/s^2$

3. $-3.66\text{m}/s^2$

4. $0\text{m}/s^2$

Q. If displacement of a particle is given as $x=t^3-2t^2$, then average acceleration from $0$ to $2$ seconds is

1. $2m/s^2$
2. $4m/s^2$
3. $8m/s^2$
4. $1m/s^2$

Q. An object is moving in a straight-line path has a velocity of $40\text{m/s}$ at some instant. After $5\text{s}$, its velocity changed to $30\text{m/s}$. What is the average acceleration of the ball during this time interval?

1. $2{\text{m/s}}^2$
2. $-2{\text{m/s}}^2$
3. $-4{\text{m/s}}^2$
4. $4{\text{m/s}}^2$

Q. A particle, moving with uniform speed $v$, changes its direction by angle $\theta$ in time $t$. Magnitude of its average acceleration during this time is

1. $\text{Zero}$
2. $\frac{2v}{t}\text{sin}\frac{\theta }{2}$
3. $\frac{v\sqrt{2}}{t}$
4. $\text{None of these}$

Q. A train accelerates from $36\text{km/h}$ to $54\text{km/h}$ in $5\text{s}$ then average acceleration of the train is

1. $1{\text{m/s}}^2$
2. $2{\text{m/s}}^2$
3. $0.5{\text{m/s}}^2$
4. $1.5{\text{m/s}}^2$

Q. A train starts from rest and accelerate uniformly at the rate of $5{\text{m/s}}^2$ for $5\text{sec}$. Calculate the velocity of train in $5\text{sec}$.

1. $20\text{m/s}$
2. $25\text{m/s}$
3. $10\text{m/s}$
4. $5\text{m/s}$

Q. When a car driver travelling at a speed of $20\text{m/s}$ applies the brakes and brings the car to rest in $4\text{sec}$, the acceleration of car will be :

1. $2{\text{m/s}}^2$
2. $3{\text{m/s}}^2$
3. $5{\text{m/s}}^2$
4. $-5{\text{m/s}}^2$

Q. An object is moving in a straight-line path has a velocity of $40\text{m/s}$ at some instant. After $5\text{s}$, its velocity changed to $30\text{m/s}$. What is the average acceleration of the ball during this time interval?

1. $2{\text{m/s}}^2$
2. $-2{\text{m/s}}^2$
3. $-4{\text{m/s}}^2$
4. $4{\text{m/s}}^2$

Q. Motion described by an object is shown in the figure given below, the acceleration of the object is

1. $5{\text{m/s}}^2$
2. $-10{\text{m/s}}^2$
3. $-5{\text{m/s}}^2$
4. $15{\text{m/s}}^2$

Q. Velocity time graph of a particle in straight line motion is in shape of a semicircle of radius $R$ as shown in figure. Its average acceleration from $t=0$ to $t=R$ is

1. $0{\text{m/s}}^2$
2. $1{\text{m/s}}^2$
3. $R{\text{m/s}}^2$
4. $2R{\text{m/s}}^2$