Homework Help: Physics

Posted by Walter on Saturday, September 10, 2011 at 8:23pm.

A small rock is thrown vertically upward with a speed of 13.0 m/s from the edge of the roof of a 20.0 m tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected.

A.) What is the speed of the rock just before it hits the street?

B.) How much time elapses from when the rock is thrown until it hits the street?

Physics - bobpursley, Saturday, September 10, 2011 at 9:33pm
a) consider energy
Intial KE+ initailPE= finalKE
1/2 m 13^3+ mg*20=1/2 m vf^2 solve for Vf.

b) time?
avg veloctity= (-13+vf )/2

time= distance/avg velocity= 2*20/(Vf-13)

Answer this Question

Related Questions

physics - A small rock is thrown vertically upward with a speed of 13.0 from the...
physics - A small rock is thrown vertically upward with a speed of 13.0from the ...
physics - A rock is thrown vertically upward with a speed of 14.0 m/s from the ...
Physics - A rock is thrown vertically upward with a speed of 11.0 from the roof ...
Physics - A rock is thrown vertically upward with a speed of 12.0 from the roof ...
physics - A rock is thrown vertically upward from the edge of a cliff. The rock ...
science - A rock is thrown vertically upward with an initial speed of 100 ft/s. ...
physics - A rock is thrown vertically upward from the ground with an initial ...
physics - A rock is thrown vertically upward from the ground with an initial ...
Physics - A rock is thrown vertically upward with a speed of 11.0 m/s from the ...

For Further Reading

First Name:
School Subject:
Answer: