MJC8719
- 41
- 0
A small block of mass m1 = 0.480 kg is released from rest at the top of a curved-shaped frictionless wedge of mass m2 = 3.00 kg, which sits on a frictionless horizontal surface as in Figure P9.60a. When the block leaves the wedge, its velocity is measured to be v1 = 3.00 m/s to the right, as in Figure P9.60b.
Figure P9.60
(a) What is the velocity of the wedge after the block reaches the horizontal surface?
m/s to the left
(b) What is the height h of the wedge?
m
You must use conservation of momentum:
m1v1 = m2v2
m1 - mass of block
m2 - mass of wedge
v1 - velocity of block
v2 - velocity of wedge
Plug in your values.
(0.480 kg)(3.00 m/s) = (3.00 kg)v2
Multiply.
1.44 kg m/s = (3.00 kg)v2
Divide both sides of the equation by 3.00 kg.
v2 = 0.48 m/s to the left
Part B
PEi + KEi = PEf + KEf
mgh + 0.5mvi2 = mgh + 0.5mvf2
mgh + .5mvi^2 = mgh + .5 mvf^2
(0.48)(9.8)(h) + .5(.48)(3^2) = 0 (as the height is now zero) + .5(.48)(.48^2)
When i solve for this I get -.4474 which is incorrect.
What am I doing wrong
Figure P9.60
(a) What is the velocity of the wedge after the block reaches the horizontal surface?
m/s to the left
(b) What is the height h of the wedge?
m
You must use conservation of momentum:
m1v1 = m2v2
m1 - mass of block
m2 - mass of wedge
v1 - velocity of block
v2 - velocity of wedge
Plug in your values.
(0.480 kg)(3.00 m/s) = (3.00 kg)v2
Multiply.
1.44 kg m/s = (3.00 kg)v2
Divide both sides of the equation by 3.00 kg.
v2 = 0.48 m/s to the left
Part B
PEi + KEi = PEf + KEf
mgh + 0.5mvi2 = mgh + 0.5mvf2
mgh + .5mvi^2 = mgh + .5 mvf^2
(0.48)(9.8)(h) + .5(.48)(3^2) = 0 (as the height is now zero) + .5(.48)(.48^2)
When i solve for this I get -.4474 which is incorrect.
What am I doing wrong