Answer to Question #56262 in Mechanics | Relativity for adeshina

Question

18 a boy throws a ball vertically upward with a speed of 15.0m/s. what is its speed just before the boy catches it again?

11.5 m/s downward

225.0 m/s downward

15.0 m/s downward

250 m/s downward



19 a ball is thrown vertically upward with a speed

v

from a point

h

metres above the ground. which of the following correctly expresses the time taken to for the ball to strike the ground?

vg(1+1+2hgv2−−−−−−−√)

vg(1−1+2hgv3−−−−−−−√)

vg(1+1−2hgv2−−−−−−−√)

vg(1+1−2hgv3−−−−−−−√)



20 a body moves along the x-axis according to the law

x=2t3+5t2+5

, where

x

is in metres. find the acceleration at

t=3s

34m/s2

46m/s2

44m/s2

36m/s2