Practice MCQ Questions and answers on Physics-GK

91

During uniform motion of an object along a straight line, its ________ remains constant with time.

A) Acceleration B) Deceleration C) Force D) Velocity

Discuss

Answer & Solution

Answer: Option D

Solution:

During uniform motion of an object along a straight line, its velocity remains constant with time.

92

Find the acceleration (in m/s²) of a body which accelerates from 25 m/s to 30 m/s in 10 seconds

A) 5.5 B) 1 C) 11 D) 0.5

Discuss

Answer & Solution

Answer: Option D

Solution:

u(initial velocity) = 25m/s
v(final velocity) = 30m/s
t(time) = 10s

a = (v-u)/t
a = (30-25)/10
a = 5/10
a = 1/2
a = 0.5m/s²

93

Acceleration is

A) Inversely proportional to force B) Inversely proportional to mass C) Directly proportional to mass D) Directly proportional to force

Discuss

Answer & Solution

Answer: Option D

Solution:

Acceleration is directly proportional to force.

94

A tennis ball machine serves a ball vertically into the air from a height of 2 feet, with an initial speed of 110 feet per second. After how many seconds does the ball attain its maximum height?

A) 2.87 sec B) 3.44 sec C) 4.65 sec D) 5.41 sec

Discuss

Answer & Solution

Answer: Option B

Solution:

It is launched vertically with an initial speed of 110 ft/sec.
It will reach maximum height when the speed drops to 0.
Vo = 110 feet per second
ho = 2 feet
So, h(t) = -16t^2 +110t +2
Take the derivative: h'(t) = 110 -32t
The maximum height will be at the inflection when the derivative crosses the x-axis, then h'(t)=0.
So, set h'(t)=0 and solve for t:
0 = 110 -32t
-110 = -32t
t = 3.4375
t = 3.44 seconds.

95

The motion of a freely falling body is an example of ________ motion.

A) Uniformly accelerated B) Non-uniformly accelerated C) Constant velocity D) Constant speed

Discuss

Answer & Solution

Answer: Option A

Solution:

The motion of a freely falling body is an example of uniformly accelerated motion. The motion of the body where the acceleration is constant is known as uniformly accelerated motion.

96

If velocity is constant then acceleration is what?

A) Constant B) Increasing C) Zero D) Infinite

Discuss

Answer & Solution

Answer: Option C

Solution:

Acceleration is defined as the change in velocity over time.
Since in this case there is no change, there is no acceleration, so it is zero.

97

Acceleration is the rate of change of

A) Speed B) Velocity C) Jerk D) Jounce

Discuss

Answer & Solution

Answer: Option B

Solution:

Acceleration is the rate of change of velocity.

98

Rate at which velocity changes over time?

A) Speed B) Displacement C) Acceleration D) Jerk

Discuss

Answer & Solution

Answer: Option C

Solution:

Rate at which velocity changes over time is called acceleration.

99

Who is the first person to define speed

A) Galileo B) Newton C) Kepler D) Ptolemy

Discuss

Answer & Solution

Answer: Option A

Solution:

The Italian physicist Galileo Galilei is credited with being the first to measure speed by considering the distance covered and the time it takes. Galileo defined speed as the distance covered per unit of time.

100

For an object, the state of rest is considered to be the state of ________ speed.

A) Increasing B) Decrease C) Inverse D) Zero

Discuss

Answer & Solution

Answer: Option D

Solution:

The state of rest is considered as state of no speed or of zero speed.