Velocity Ratio

Q. A body $A$ starts from rest with an acceleration $a_1$ . After $2$ seconds, another body $B$ starts from rest with an acceleration $a_2$ . If they travel equal distances in the $5^{\text{th}}\text{second}$ after the start of $A$, then the ratio $a_1:a_2$ is equal to

1. $5:9$
2. $5:7$
3. $9:5$
4. $9:7$

Q. In an ideal machine, mechanical advantage is to velocity ratio.

1. less than
2. equal to
3. greater than

Q. A person completes half of his journey with speed $v_1$ and rest half with speed $v_2$. The average speed ($v_{avg})$ of the person is

1. $\frac{v_1+v_2}{2}$
2. $\frac{2v_1{v}_2}{v_1+v_2}$
3. $\frac{v_1{v}_2}{v_1+v_2}$
4. $\sqrt{v_1{v}_2}$

Q.

What is the magnitude of force needed to produce an acceleration of 4 m/s² in a ball of 6 kg?

1. 30N

2. 24N

3. 20N

4. 26N

Q.

Define the term velocity ratio. State its unit.

Q.

The rate of change of motion is called?

Q.

$OA$ and $OB$ are two roads enclosing an angle of ${120}^{°}$ $X$and $Y$ start from $O$ at the same time. $X$ travels along $OA$ with a speed $4\text{km/hour}$ and $Y$ travels along $OB$ with a speed $3\text{km/hour}$. The rate at which the shortest distance between $X$and $Y$ is increasing after $1\text{hour}$ is

1. $\sqrt{37}\text{km/h}$

2. $37\text{km/h}$

3. $13\text{km/h}$

4. $\sqrt{13}\text{km/h}$

Q.

The ratio of the load to the effort is______.

Q. A lead bullet strikes against a steel armor plate with the velocity of 300 meter/second. If the bullet, assuming that the impact is perfectly inelastic find the rise in temperature of the bullet. Assume that the heat produced is shared equally between the bullet and the target, specific heat of lead = $0.03cal/g{/}^{\circ }C$

1. 
2. 
3. 
4. 

Q.

What is the expression for Velocity Ratio (VR), if the velocity of effort and the velocity of the load are denoted as V1 and V2 respectively?

1. (V1 + V2) / V2

2. V1 / (V1 + V2)

3. V1 / V2

4. V2 / V1

Q.

A machine works as a (i) force multiplier, (ii) speed multiplier. In each case state whether the velocity ratio than or less than 1.

Q. What is the velocity ratio of this gear system?

1. 1:1
2. 1:2
3. 2:1
4. Can't be calculated

Q.

A student at the top of a building of height $h$ throws one ball upward with an initial velocity $v_i$and then throws a second ball downwards with the same initial speed. How were the final velocities of the ball to compare when they reach the ground?

Q. The expression for Velocity Ratio $V.R$, if the velocity of load and the velocity of the effort are denoted as $V_1$ and $V_2$ respectively is .

1. $V_1+V_2=0$
2. $\frac{V_1}{V_2}$
3. $\frac{V_2}{V_1}$
4. $V_1=V_2$

Q.

The distance traveled by a body falling freely from rest in 2^nd, 3^rd and 5^th second of its motion is in the ratio of

1. 7:5:3

2. 3:5:9

3. 5:3:7

4. 5:7:3

Q.

What is the unit of the velocity ratio?

1. Unitless
2. Square metre
3. Newton metre
4. Metre per second

Q. Why is mechanical advantage less than the velocity ratio of a real machine ?

Q. In a certain machine a force of $100$ N moves down a distance of $20$ cm in order to raise a load of $220$ N through a height of $1$ cm. Calculate the velocity ratio of machine.

1. 10
2. 22
3. 20
4. 260

Q. Why velocity ratio is greater than mechanical advantage in a simple machine?

Q. A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant, the gun fires 10 bullets/second, each of mass 10 g with a velocity of 500 m s${}^{-1}$. The acceleration of the car is

1. 0.025 ms${}^{-2}$
2. 0.25 ms${}^{-2}$
3. 0.5 ms${}^{-2}$
4. 500 ms${}^{-2}$

Q. Relationship between the mechanical advantage and velocity ratio of an ideal machine is

1. Velocity ratio > Mechanical advantage
2. All
3. Velocity Ratio < mechanical advantage
4. Velocity Ratio = Mechanical advantage

Q.

What is the unit of Velocity Ratio?

1. Unitless

2. m/s

3. m/s^2

4. N-m/s

Q.

Now Tony settles upon a Carnot engine. Calculate the efficiency of the Carnot engine if the temperature it operates between are 350 K and 250 K.

1. 2/7

2. 3/7

3. 5/7

4. 4/7

Q. Velocity Ratio of a machine is more than 1. It

1. Gives loss of speed
2. Either A or B
3. Acts as a force multiplier
4. A and B

Q. Relationship between mechanical advantage and velocity ratio for a practical machine is

1. Velocity ratio > Mechanical advantage
2. Velocity ratio < mechanical advantage
3. Velocity ratio = Mechanical advantage
4. All

Q. The unit of velocity ratio is $\frac{m}{s}$.

1. False
2. True

Q.

The required Velocity Ratio(V.R) for a machine whose effort distance is 3 times that of load distance is ___ .

Q. In an ideal machine, mechanical advantage is to velocity ratio.

1. less than
2. equal to
3. greater than

Q. The required Velocity Ratio (V.R) for a machine whose effort distance is 3 times that of load distance is ___ .

1. $3$
2. $8$
3. $\frac{1}{3}$
4. $\frac{1}{8}$

Q. In a lifting machine, an effort of 500 N is to be moved by a distance of 20 m to raise a load of 10, 000 N by a distance of 0.8 m. Determine the effort lost in friction

1. 100 N
2. 120 N
3. 80 N
4. 0 N