A horizontal force of 120 N is required to push a bookcase across the floor at a constant velocity how much is the friction forc
1 answer:
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Answer:
6.86 meters
Explanation:
Let the compression of the string be represented by x, and the height of projection of the toy rocket be represented by h.
So that;
x = 9 cm = 0.09 m
In its rest position (i.e before the launch), the spring has a stored potential energy which is given as;
PE = K
= x 830 x
= 415 x 0.0081
= 3.3615
The potential energy in the string = 3.36 Joules
Also,
PE = mgh
where: m is the mass, g is the gravitational force and h the height.
m = 50 g = 0.05 kg, g = 9.8 m
Thus,
PE = 0.05 x 9.8 x h
3.3615 = 0.05 x 9.8 x h
3.3615 = 0.49h
⇒ h =
= 6.8602
The height of the toy rocket would be 6.86 meters.
The gravitational potential energy U is defined as the product of mass m, the acceleration of gravity g and the height of object h.
We do not have the mass of the hiker. But we know that its W weight is:
Where
So:
.
So:
J
The hiker has gained 30,000 J of energy