Question 11

A bullet fired vertically upward from a gun held 2.0m above the ground reaches its maximum height in 4.0 s. calculate its initial velocity. {2009}

A.10ms^{-1 } B.8ms^{-1} C. 40ms^{-1} D. 20ms^{-1}

^{-2}]

Solution

C is the correct option

Question 12

An object of mass 80kg is pulled on a horizontal rough ground by a force of 500N. Find the coefficient of static friction. {2009}

A.0.8 B. 0.4 C. 1.0 D. 0.6

[g = 10ms^{-2}]

Solution

D is the correct option

Question 13

Two cars moving in the same direction have speeds of 100kmh^{-1} and 130kmh^{-1}. What is the velocity of the faster car as measured by an observer in the slower car? {2010}

A.130kmh^{-1} B. 230kmh^{-1} C. 200kmh^{-1} D. 30kmh^{-1}

Solution

You are to calculate the relative speed

D is the correct option

Question 14

A car moves with an initial velocity of 25ms^{-1} and reaches a velocity of 45ms^{-1} in 10s. What is the acceleration of the car?{2010}

- 5ms
^{-1}B. 25ms^{-1}C. 20ms^{-1}D. 2ms^{-1}

Solution

D is the correct option

Question 15

Two balls X and Y weighing 5g and 50kg respectively were thrown up vertically at the same time with a velocity of 100ms^{-1}. How will their positions be one second later? {2011}

A. X and Y will both be 500m from the point of throw

B. X and Y will be 500m from each other

C. Y will be 500 m ahead of X

D. X will be 500m ahead of Y.

Solution

The distance covered after one second

S = 500m

The position the two balls will be from the point of throw is independent on their mass.

A is the correct option

Question 16

If it takes an object 3s to fall freely to the ground from a certain height, what is the distance covered by the object?

A. 60 m B. 90 m C. 30 m D. 45 m.

[g = 10ms^{-2}]

Solution

Initial velocity = 0

S = 45m

D is the correct option

Question 17

Calculate the total distance covered by a train before coming to rest if its initial speed is 30ms^{-1} with a constant retardation of 0.1ms^{-2}. {2012}

A. 5500m

B. 4500m

C. 4200m

D. 3000m.

Solution

V = 0

U =30ms^{-1}

a=-0.1ms^{-2}

The a is negative because the motion is retarding i.e. deceleration

S = 4500 m

B is the correct option

Question 18

A car starts from rest and moves with a uniform acceleration of 30ms^{-2} for 20s. Calculate the distance covered at the end of the motion.{2012}

A. 6km

B. 12km

C. 18km

D. 24km.

Solution

S = 6000m = 6km

A is the correct option

Question 19

An object of mass 20kg slides down an inclined plane at an angle of 30^{o} to the horizontal. The coefficient of static friction is {2012}

A. 0.2 B. 0.3 C. 0.5 D. 0.6

[g = 10ms^{-2}]

Solution

D is the correct answer

Question 20

A train with an initial velocity of 20ms^{-1} is subjected to a uniform deceleration of 2ms^{-2}. The time required to bring the train to a complete halt is

- 40s B. 5s C. 10s D. 20s

Solution

V = 0

U = 20

a= -2

C is the correct option

Question 21

Calculate the apparent weight loss of a man weighing 70kg in an elevator moving downwards with an acceleration of 1.5ms^{-2}. {2013}

A. 105N B. 686N C. 595N D. 581N

Solution

The apparent weight loss = ma = 70 * 1.5 = 105N

A is the correct option

Question 22

The coefficient of friction between two perfectly smooth surface is {2013}

A. Zero B. Infinity C. One D. Half

Solution

A is the correct option