Answer:
The time taken to rotate the sphere one time is, t = 22 s
Explanation:
Given data,
The mass of the sphere, m = 8200 kg
The radius of the sphere, r = 90 cm
= .9 m
The force applied by the girl, F = 75 N
The moment of inertia of the sphere is,
I = 2/5 mr²
= (2/5) 8200 x (.9)²
= 2657 kg·m²
The torque,
τ = I α
75 x 0.9 = 2657 x α
α = 0.0254 rad/s²
The angular displacement,
θ = ½αt²
2π = ½ x 0.0254 rad/s² x t²
t = 22 s
Hence, the time taken to rotate the sphere one time is, t = 22 s
The storm is moving toward you at 35km/hr. How long until it travels to 80 kilometers to your house?
Distance = velocity * time
80km = 35 km/hour * x hours Divide both sides by 35
2.29 hours = x
It will take 2.29 hours to reach your house.
Answer:
5398.4km/h
Explanation:
IN THIS CASE THE MOMENTUM IS CONSERVED. THE VALUE OF MOMENTUM OF ONE COMBINED ROCKET WILL BE SAME AS OF TWO COMBINED.
Let mass of module be m
then
mass of motor = 4m (four times the mass of rocket module)
total mass = m + 4m = 5m
combined velocity = V = 5320kph
Let
absolute (relative to earth)motor velocity after disengagement = v
then
rocket module velocity (relative to earth) after disengagement = v+98 (relative velocity = 98)
momentum conservation equation
combined momentum = module momentum + motor momentum
(m+4m)V = m(v+98) + 4m*v
5mV = 98m+mv + 4mv
5V = 98+v + 4v (m cancels out)
5V - 98 = 5v
((5*5320)-98)/5 = v
v = 5300.4 km/h
velocity of rocket module relative to earth = v +98
= 5300.4 + 98
= 5398.4km/h
