A coin is thrown in a vertically upward direction with a velocity of 5 ms−1. If the acceleration of the coin during its motion is 10 ms−2 in the downward direction, what will be the height attained by the coin and how much time will it take to reach there ?
The correct option is D s=1.25 m, t=0.5 s
Step 1, Given data
Initial velocity, u=5 ms−1,
Acceleration, a=−10 ms−2.
Let 'v' be the final velocity and 's' be the height attained.
At the highest point of motion, v=0
Step 2, Finding time
Using third equation of motion, v2=u2+2as,
0=52+[2×(−10)×s]
⇒s=1.25 m
Hence the height attained by the coin is 1.25 m.
Let the time taken be t.
Using the first equation of motion,
v=u+at
0=5−10t
⇒t=0.5 s
∴ Time taken by the coin is 0.5 s.