Speed

Q.

Can a body have a constant velocity and still have a varying speed?

Q. Speed is a _____ quantity but velocity is a _________ quantity.

1. scalar, scalar
2. vector, vector
3. vector, scalar
4. scalar, vector

Q.

Velocity does not change when direction changes.

1. True
2. False

Q. "The tip of second hand" of the clock takes $60\text{s}$ to move once on the circular dial of the clock. If the length of the second hand is $10\text{cm}$, calculate the speed of the tip of the second hand clock ?

$(\pi =22/7)$

1. $0.04\text{m/s}$
2. $0.02\text{m/s}$
3. $0.01\text{m/s}$
4. $0.03\text{m/s}$

Q. A motorcyclist drives from place $A$ to $B$ with a uniform speed of $30\text{km/h}$ and returns from place $B$ to $A$ with a uniform speed of $20\text{km/h}$. Find his average speed.

1. $25\text{km/h}$
2. $20\text{km/h}$
3. $24\text{km/h}$
4. $28\text{km/h}$

Q. A motorcyclist drives from place $A$ to $B$ with a uniform speed of $30\text{km/h}$ and returns from place $B$ to $A$ with a uniform speed of $20\text{km/h}$. Find his average speed.

1. $25\text{km/h}$
2. $20\text{km/h}$
3. $24\text{km/h}$
4. $28\text{km/h}$

Q.

A 150 m long train is moving with a uniform velocity of 45 km/h. The time taken by the train to cross a bridge of length 850 meters is

1. 56 sec

2. 68 sec

3. 80 sec

4. 92 sec

Q. The slope of distance-time graph gives

1. acceleration
2. velocity
3. speed
4. displacement

Q. A drunkard takes a step of $1\text{m}$ in 1 second. He takes 5 steps forward and 3 steps backwards, and so on. The time taken by him to fall in a pit $13\text{m}$ away from the starts is

1. 26 seconds
2. 31 seconds
3. 37 seconds
4. 41 seconds

Q. The $x-t$ graph of a particle undergoing a simple harmonic motion is shown here. The acceleration of the particle at $t=\frac{4}{3}\text{s}$ is

1. $\frac{-{\pi }^2}{32}{\text{cm s}}^{-2}$
2. $\frac{\sqrt{3}{\pi }^2}{32}{\text{cm s}}^{-2}$
3. $\frac{{\pi }^2}{32}{\text{cm s}}^{-2}$
4. $-\frac{\sqrt{3}{\pi }^2}{32}{\text{cm s}}^{-2}$

Q.

A body can have a constant speed and still have varying velocities.

1. True
2. False

Q. Superman and Batman took part in a race. The race involved going from $A$ to $B$ {1 km straight line} and coming back to $A$ along the same line. Superman ran with a constant speed of $15$ m/s both ways. Batman on his way from $A$ to $B$ ran at a constant speed of $10$ m/s but on his way back cheated by using his car which moved at a speed of $20$ m/s. Who won the race?

1. Batman
2. Superman
3. Race ended in a tie
4. Data insufficient

Q. A source of sound S is travelling at $\frac{100}{3}m/s$ along a road, towards a point A. When the source is 3 m away from A, a person standing at a point O on a road perpendicular to AS hears a sound of frequency v’. The distance of O from A at that time is 4m. If the original frequency is 640 Hz, then the value of v’ is (velocity of sound is 340 m/s)

1. 620 Hz
2. 680 Hz
3. 720 Hz
4. 840 Hz

Q. The $x-t$ graph of a particle undergoing a simple harmonic motion is shown here. The acceleration of the particle at $t=\frac{4}{3}\text{s}$ is

1. $-\frac{\sqrt{3}{\pi }^2}{32}{\text{cm s}}^{-2}$
2. $\frac{\sqrt{3}{\pi }^2}{32}{\text{cm s}}^{-2}$
3. $\frac{-{\pi }^2}{32}{\text{cm s}}^{-2}$
4. $\frac{{\pi }^2}{32}{\text{cm s}}^{-2}$