Aprojectile of mass 0.850 kg is shot straight up with an initial speed of 30.0 m/s. (a) how high would it go if there were no air resistance? (b) if the projectile rises to a maximum height of only 36.7 m, determine the magnitude of the average force due to air resistance.

a) 45.87 m

b) 2.08 N

Explanation:

Mass of projectile=0.85 kg=m

Velocity of projectile=30 m/s=u = initial velocity

Final velocity =0

g= acceleration due to gravity=9.81 m/s²

h=maximum height of the projectile

a) In this case loss of Kinetic energy (K.E.) = loss in potential energy (P.E.)

ΔK.E.=ΔP.E.

b) h'=height of the projectile=36.7 m

F=Average force due to air resistance

There will be a loss of P.E. due to air resistance

ΔP.E.=mg(h-h')

F×h'=mg(h-h')

F×36.7=0.85×9.81(45.87-36.7)

∴ F=2.08 Newton

wind moving at higher speeds will transfer more energy to the water, resulting in stronger waves.