Figure 8-31 shows a ball with mass m = 0.341 kg attached to the end of a thin rod with length L = 0.452 m and negligible mass. The other end of the rod is pivoted so that the ball can move in a vertical circle. The rod is held horizontally as shown and then given enough of a downward push to cause the ball to swing down and around and just reach the vertically up position, with zero speed there. How much work is done on the ball by the gravitational force from the initial point to (a) the lowest point, (b) the highest point, and (c) the point on the right level with the initial point? If the gravitational potential energy of the ball–Earth system is taken to be zero at the initial point, what is it when the ball reaches (d) the lowest point, (e) the highest point, and (f) the point on the right level with the initial point? (g) Suppose the rod were pushed harder so that the ball passed through the highest point with a nonzero speed. Would Δ U g from the lowest point to the highest point then be greater than, less than, or the same as it was when the ball stopped at the highest point? Figure 8-31 Problems 4 and 14.
Figure 8-31 shows a ball with mass m = 0.341 kg attached to the end of a thin rod with length L = 0.452 m and negligible mass. The other end of the rod is pivoted so that the ball can move in a vertical circle. The rod is held horizontally as shown and then given enough of a downward push to cause the ball to swing down and around and just reach the vertically up position, with zero speed there. How much work is done on the ball by the gravitational force from the initial point to (a) the lowest point, (b) the highest point, and (c) the point on the right level with the initial point? If the gravitational potential energy of the ball–Earth system is taken to be zero at the initial point, what is it when the ball reaches (d) the lowest point, (e) the highest point, and (f) the point on the right level with the initial point? (g) Suppose the rod were pushed harder so that the ball passed through the highest point with a nonzero speed. Would Δ U g from the lowest point to the highest point then be greater than, less than, or the same as it was when the ball stopped at the highest point? Figure 8-31 Problems 4 and 14.
Figure 8-31 shows a ball with mass m = 0.341 kg attached to the end of a thin rod with length L = 0.452 m and negligible mass. The other end of the rod is pivoted so that the ball can move in a vertical circle. The rod is held horizontally as shown and then given enough of a downward push to cause the ball to swing down and around and just reach the vertically up position, with zero speed there. How much work is done on the ball by the gravitational force from the initial point to (a) the lowest point, (b) the highest point, and (c) the point on the right level with the initial point? If the gravitational potential energy of the ball–Earth system is taken to be zero at the initial point, what is it when the ball reaches (d) the lowest point, (e) the highest point, and (f) the point on the right level with the initial point? (g) Suppose the rod were pushed harder so that the ball passed through the highest point with a nonzero speed. Would ΔUgfrom the lowest point to the highest point then be greater than, less than, or the same as it was when the ball stopped at the highest point?
A 5 kg cylinder 0.5 m in diameter rolls down a plane 5 m long inclined 30° with the horizontal at the bottom of the incline. What is its (a) total kinetic energy, (b) linear speed, (c) angular speed, (d) rotational kinetic energy, and (e) translational kinetic energy? Neglect friction.
A lawnmower engine brings a 1 m-long by 0.1 m-wide cutting blade of mass 2.55 kg from rest to an angular speed of 1800 rpm in 1.27 seconds. What is the average power supplied by the engine during this period?
2910 W
2940 W
2970 W
3000 W
3030 W
A matchbox car track begins at a height y=1.0, goes down hill to y=0, goes around a vertical loop of radius 0.2 m and then goes back up a smaller hill to end at a height y=0.3 m. The speed of the car at the end of the track is closest to which value?
Conceptual Physics: The High School Physics Program
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