Question

A particle at rest starts from the origin with a constant acceleration a that makes an angle 60° with the positive y-axis. If its displacement along y-axis is 10m in time 2s,then the magnitude of a is:

• A. 10ms-2
• B. 4ms-2
• C. 8ms-2
• D. 15ms-2
• E. 20ms-2

Answer 1

Answer: (A)

10ms-2

Answer 2

The correct option is (A): 10ms-2
$y=\frac{1}{2}(a\,cos(60^0=>10=\frac{1}{2}(a.\frac{1}{2})$ (4)
$10=\frac{1}{2}(\frac{a}{2})4=>10=a$
Thus, the magnitude of a is confirmed to be 10ms-2