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URGENT! 40 POINTS! For each situation below, find the work done on the box using both energy and forces.

1. A 2 kg box initially at rest slides down a frictionless ramp (at 15ᵒ from the ground) for
1 second.

2. A 2 kg box is thrown upward with an initial speed of 3.5 m/s. Consider the box from
the time it was thrown until it reaches its maximum height.

3. A 2 kg box is dropped from an initial height of 10 m.


I have some physics, I just don't know what formulas to use or where to start. Help is much appreciated.

2 Answers

1 vote

Answer:

i’m not sure one second let me try to figure it out

Step-by-step explanation:

User Cklm
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In scenario 1, the box sliding down a ramp, the energy approach yields -196.2 J, and the forces approach calculates 9.82 J. For scenario 2, the box thrown upward, the energy approach results in -24.5 J, and the forces approach gives 120.07 J. In scenario 3, the box dropped from height, the energy approach indicates -196.2 J, and the forces approach computes 196.2 J. Energy approaches consider changes in potential or kinetic energy, while forces approaches involve the force applied and distance traveled.

Scenario 1: Box sliding down a frictionless ramp

Energy Approach

Initial potential energy: 2 kg * 9.81 m/s^2 * 10 m = 196.2 J

Final potential energy: 0 J

Change in potential energy: -196.2 J

Work done by gravity: -196.2 J

Forces Approach

Force of gravity: 2 kg * 9.81 m/s^2 = 19.62 N

Angle of the ramp: 15 degrees

Component of force parallel to the ramp: 19.62 N * sin(15 degrees) = 4.91 N

Distance traveled: d = vt = (1 s) * (2 m/s) = 2 m

Work done by gravity: 4.91 N * 2 m = 9.82 J

Scenario 2: Box thrown upward

Energy Approach

Initial kinetic energy: 0.5 * 2 kg * (3.5 m/s)^2 = 24.5 J

Final kinetic energy: 0 J

Change in kinetic energy: -24.5 J

Work done by gravity: -24.5 J

Forces Approach

Force of gravity: 2 kg * 9.81 m/s^2 = 19.62 N

Displacement: d = h = (v^2 - u^2) / (2a) = (0^2 - (3.5 m/s)^2) / (2 * -9.81 m/s^2) = 6.08 m

Work done by gravity: 19.62 N * 6.08 m = 120.07 J

Scenario 3: Box dropped from an initial height

Energy Approach

Initial potential energy: 2 kg * 9.81 m/s^2 * 10 m = 196.2 J

Final potential energy: 0 J

Change in potential energy: -196.2 J

Work done by gravity: -196.2 J

Forces Approach

Force of gravity: 2 kg * 9.81 m/s^2 = 19.62 N

Displacement: d = h = 10 m

Work done by gravity: 19.62 N * 10 m = 196.2 J

User Joshua Martell
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