I think i used calulater and it gives me 47.5
Explanation:
The given data is as follows.
k = 130 N/m,
= 17 cm = 0.17 m (as 1 m = 100 cm)
mass (m) = 2.8 kg
When the spring is compressed then energy stored in it is as follows.
Energy = 
Now, spring energy gets converted into kinetic energy when the box is launched.
So,
= 
= 

= 1.34
v = 1.15 m/sec
Now,
Frictional force = 
= 
= 4.116 N
Also, Kinetic energy = work done by friction
1.8515 =
d = 0.449 m
Thus, we can conclude that the box slides 0.449 m across the rough surface before stopping.
Depends on how well built he is probably for the average American 8 MPH
Momentum is a property of moving objects but not stationary objects. You can see this in the formula because momentum equals mass times velocity squared (p=m*v^2). You would not have momentum if you didn't have velocity. Stationary objects have potential energy, and things with potential energy do not have velocity. This is why momentum is a property of moving objects but not of stationary objects.
Answer:
PE=0.29J
Explanation:
According to the description, there is a angle and in point swung upward of 70°
So,

Appling the equation of Potential Energy we have,
