The 0.2kg box below slides down a curved ramp, jumps a smallgap and lands on a f
ID: 2262237 • Letter: T
Question
The 0.2kg box below slides down a curved ramp, jumps a smallgap and lands on a flat platform. At the point on the rampshown it is 1.5m above the floor and it's speed is 2.0m/s. Atthe point shown on the platform the box is 0.4m above the floor andsliding at 4.2m/s. a) How much energy has been converted to non-mechanical form(mostly thermal/internal energy) as the box moves between the twopoints shown? b) Further down the ramp the object comes to rest. Howmuch energy has been converted to non-mechanical form as the boxmoves between the initial point shown and the point where the boxstops?All solutions must be based on work and/or energymethods. The 0.2kg box below slides down a curved ramp, jumps a smallgap and lands on a flat platform. At the point on the rampshown it is 1.5m above the floor and it's speed is 2.0m/s. Atthe point shown on the platform the box is 0.4m above the floor andsliding at 4.2m/s. a) How much energy has been converted to non-mechanical form(mostly thermal/internal energy) as the box moves between the twopoints shown? b) Further down the ramp the object comes to rest. Howmuch energy has been converted to non-mechanical form as the boxmoves between the initial point shown and the point where the boxstops?
All solutions must be based on work and/or energymethods.
Explanation / Answer
a)
work done by friction + workdone by gravity = change in kinetic energy
Wg + Wf = 0.5*m*(v2^2-v1^2)
0.2*9.8*(1.5-0.4) + Wf = 0.5*0.2*(4.2^2-2^2)
2.156 + Wf = 1.364
Wf = 1.364-2.156 = -0.792
work done by friction = thermal energy generated = 0.792 J
b)b)
work done by friction + workdone by gravity = change in kinetic energy
Wg + Wf = 0.5*m*(v2^2-v1^2)
0.2*9.8*(1.5-0) + Wf = 0.5*0.2*(0 - 2^2)
2.744 + Wf = -0.4
Wf = -0.4-2.744 = -3.144
work done by friction = thermal energy generated = 3.144 J
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