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21 votes
21 votes
an object from 10.0 meters. She knows it had 50.0 joules of potential energy. How much mass does it have?

User Michael Petrov
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1 Answer

10 votes
10 votes

Answer:

5N

Step-by-step explanation:

Work done by a constant force is given by the following equation:

W=F⋅d⋅cos(θ)

where F is the applied force, d is the distance over which the force is applied, and θ is the angle between the force and displacement vectors.

In this case, the work is done by gravity, and as the object is assumed to fall straight down, θ=0^o.

We know that the force of gravity acting on an object can be expressed by FG=mg, and for an object which is not accelerating (e.g. a stationary object), this is equal to the object's weight.

We know d=10m,θ=0^o and W=50J, so we can solve for F to find the object's weight. ⇒F=Wdcos (θ) But cos (0^o)=1, so: F=Wd=50J10m=5N

User Galdre
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