Question

A body is thrown vertically upwards with a speed of 100 m/s. On the return journey, the speed in m/s at the starting point will be

A) 100 m/s
B) 9.8 m/s
C) 100 x 9.8 m/s
D) 100/9.8 m/s​

Answer 1

Answer:

Opt A - 100 m/s

Step-by-step explanation:

The quetion simply asks the final velocity

Let final velocity - v m/s

At the top point of its journey, it's velocity is zero, u = 0 m/s

Acceleration - a = 9.8 m/s^2

Time it takes to to go from top point to bottom point will be half of total time taken for journey.

Time taken for whole journey is given by

2u/g, thus to reach from top point to bottom, it will be u/g = 100/9.8 s

Time = 100/9.8

By the first equation of motion,

v = u + at

v = 0 + 9.8 × 100/9.8

v = 100 [ As 9.8 and 9.8 gets cancelled ]

Hope this helps you understand

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Answer 2

Answer:9.8

Step-by-step explanation: