Question

Luigi jumps straight upwards 15.0m/s. How high is he when he is jumping at :8.0 m/s upwards

Answer 1

Given: Initial velocity $v_i= 15.0m/s$

           Final Velocity $v_f=8.0 m/s$

To find : Height when jumpled 8.0 m/s upwards.

Solution: We already have values of initial velocity and final velocity.

We know, accereration due to gravity is given by $a= -9.8 m/s^2$.

It's negative because when jump it's in opposite direction.

$We know formula, v_f ^2 = v_i ^2+2ah.$

Where h is the height when jumpled 8.0 m/s upwards.

Plugging values of $v_i, \ v_f \ and \ a \ in \ formula \ above.$

$(8.0)^2 = (15.0)^2 +2(-9.8)*h$

64= 225 -19.6h

Subtracting both sides by 225.

64-225= 225 -19.6h-225.

We get,

-161 = -19.6h

Dividing both sides by -19.6, we get

$\frac{-161 }{-19.6} =\frac{ -19.6h}{ -19.6}$

h= 8.2143

Rounding to nearest tenth, we get

h= 8.2 meter.

His height is 8.2 meter when he is jumping 8.0 m/s upwards.