Answer:
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.
[tex]\frac{1}{2}mu^2-\frac{1}{2}mv^2=mgh[/tex]
[tex]\frac{1}{2}m\times u^2=mgh\\\Rightarrow h=\frac {u^2}{2\times g}\\\Rightarrow h=\frac {30^2}{2\times 9.81}\\\therefore h=45.87\ m[/tex]
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)
[tex]F=\frac{0.85\times 9.81(45.87-36.7)}{36.7}[/tex]
∴ F=2.08 Newton
