Question

Michael Jordan has a vertical leap of 1.25 m, what is his take-off speed and for how much time he will be in the air? Take a = 10 m/s² downwards.

• A. u = 10 m/s, t = 1 s
• B. u = 5 m/s, t =0.5 s
• C. u = 15 m/s, t = 1.5 s
• D. u = 10 m/s, t = 0.5 s

Answer 1

The correct option is B

u = 5 m/s, t =0.5 s

From third equation of motion, $v^2=u^2+2as$

$0=u^2-2\times 10\times 1.25$

$u=5m/s$

Now from first equation of motion, $v=u+at$

$0=5-10\times t$

$t=\frac{5}{10}=0.5s$