Motion in A Straight Line - Online Test

Answer : Option A
Explaination / Solution:

Let's let west direction as +ve.

Initial velocity u = + 20.0 m/s

Final velocity = ?

Acceleration a = - 1.0 m/s​​​​​​2

Time taken t = 37.0 s

We know,

v = u + at

=> v=20.0−37.0×1

=> v = -17.0

-ve sign shows direction of velocity is opposite. So velocity is 17.0 m/s due east.

Answer : Option A
Explaination / Solution:

the slope of the x-t grpah will give you velocity. So, if u=0, the slope of graph at t=0 is 0.

for u>0 case, the initial slope is +ve and for negative u, the initial slope is negative now, s = ut + 0.5at2, where acceleration=a let initial position is x​​​​​​o,

x=x​​​​​​xo+ut+0.5at2 ,

Hence you will get parabolic shapes.

Answer : Option A
Explaination / Solution:

When velocity – time graph is plotted for an object moving with uniform acceleration, the slope of the graph is a straight line. 

Answer : Option C
Explaination / Solution:

The area under the velocity-time curve between times t​​​​​​1 and t​​​​​​2 is equal to the displacement of the object during that interval of time.

Answer : Option D
Explaination / Solution:

Relative velocity of a body A with respect to another body B, when both are in motion, is the velocity with which A appears to move to B.

In general,

VBA=VB−VA

Answer : Option C
Explaination / Solution:

Point object is an expression used in kinematics branch of physics: it is an object whose dimensions are ignored or neglected while considering its motion. The size of a carriage is very small as compared to the distance between two stations. Therefore, the carriage can be treated as a point sized object.

Answer : Option B
Explaination / Solution:

The voltage in India is 220 volts, alternating at 50 cycles (Hertz) per second. This is the same as, or similar to, most countries in the world including Australia, Europe and the UK.

Answer : Option D
Explaination / Solution:

Velocity is given by:

v = dsdt= d(10t+4t2)dt= 10+8t

Velocity at t=0, v0=10+8×0=10 m/s

Answer : Option B
Explaination / Solution:

Acceleration is the rate of change of velocity of an object with respect to time.

a = change in velocitytime taken

SI unit of velocity = m/s

SI unit of time = s

So SI unit of acceleration = ms×s=m/s2

Answer : Option D
Explaination / Solution:

A speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of a vehicle. Now universally fitted to motor vehicles, they started to be available as options in the 1900s, and as standard equipment from about 1910 onwards. Speedometers for other vehicles have specific names and use other means of sensing speed. For a boat, this is a pit log. For an aircraft, this is an airspeed indicator. Charles Babbage is credited with creating an early type of a speedometer, which were usually fitted to locomotives.