Question

An object is projected from the ground with an upward speed of ų m/s has a speed of 23m/s when it is at a height of 5m above the ground .Use work energy principle to determine the initial speed u.​

Answer 1

25.08m/s

Step-by-step explanation:

mgh1 + 0.5mv1² = mgh2 + 0.5mv2²

h1 = 0m

v1 = u

h2 = 5m

v2 = 23m/s

putting the values into the formula above;

m(10)(0) + 0.5m(u²) = m(10)(5) + 0.5m(23²)

0 + 0.5mu² = 50m + 264.5m

0.5mu² = 314.5m

dividing through by m

0.5u² = 314.5

u² = 629

u = 25.08m/s

Therefore, the initial speed "u" = 25m/s