# Calculating resultant force and change in potential energy

The speed of a 4.0kg object is given by (2t) m/s, where t is in seconds. At what rate is the resultant force on this object doing work at t = 1 second?

Answers:

a) 48 W

b) 40 W

c) 56 W

d) 16 W

A 10kg object is initially at the top of a rise, at point A. It then moves down to point B. Choose point B to be your zero level for gravitational potential energy. Find the change in potential energy of the object if point B is 10m lower than point A?

Answers:

a) -980

b) -10

c) -100

d) -98

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OTA: Please take this problem only if you can show step by step problem solving and equations used. Thank you.

https://brainmass.com/physics/power/calculating-resultant-force-and-change-in-potential-energy-23286

#### Solution Preview

First part.

Given: v= 2t so initial velocity at t=0 is: Vo= 0

At t= 1 sec, Vf= 2 m/sec.

Acceleration is: a= (Vf - Vo)/t = (2 m/sec - 0)/( ...

#### Solution Summary

This solution is provided in 156 words. It uses equations for acceleration, resultant force, and power to find the rate of work. It also calculates loss of potential energy.