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nothing4me
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I have a test in a day and I basically know almost everything. We were handed out a packet of about 50 questions for practice. I've gotten everything but these 6 problems.
I have the answers, but I'm clueless on how to get them. I have an A average in Physics AP and would like to keep that, haha. Could anyone help me figure these problems out? (Instructions) Thanks!
1. In space, a 70.0-kg astronaut pushes to the left on a spacecraft with a force R. The spacecraft has a total mass of 1.0 x 10^4 kg. During the push, the astronaut accelerates to the right with an acceleration of 0.36 m/s2. Determine the magnitude of the acceleration of the spacecraft . [Answer: 2.5 x 10^-3 m/s2]
2. A muscle builder holds the ends of a massless rope. At the center of the rope, a 15-kg ball is hung. What is the tension in the rope if both angles θ are 4.5°. (The angles are under, respecting the horizontal line.) [Answer: 940N]
3. If the coefficient of kinetic friction, μk, between a block and the surface is .30 and the magnitude of the frictional force is 80N, what is the weight of the block? [Answer: 4.0]
4. A 250-N force is directed horizontally to push a 29-kg box up an inclined plane (27 degrees respect to the horizontal) at a constant speed. Determine the magnitude of the normal force, FN, and the coefficient of kinetic friction, µk. [Answer: 370N and .26]
5. A 2.0-N rock slides on a frictionless inclined plane. Which one of the following statements is true concerning the normal force that the plane exerts on the rock?
A) The normal force is zero Newtons.
B) The normal force is 2.0 N.
C) The normal force is greater than 2.0 N.
D) It increases as the angle of inclination, q, is increased.
E) The normal force is less than 2.0 N, but greater than zero Newtons. [Answer: E]
6. Two forces act on a 4.5-kg block resting on a frictionless surface as shown. What is the magnitude of the horizontal acceleration of the block? Link to image: http://img363.imageshack.us/img363/6591/picki0.jpg [Answer: 1.8 m/s2]
I have the answers, but I'm clueless on how to get them. I have an A average in Physics AP and would like to keep that, haha. Could anyone help me figure these problems out? (Instructions) Thanks!
1. In space, a 70.0-kg astronaut pushes to the left on a spacecraft with a force R. The spacecraft has a total mass of 1.0 x 10^4 kg. During the push, the astronaut accelerates to the right with an acceleration of 0.36 m/s2. Determine the magnitude of the acceleration of the spacecraft . [Answer: 2.5 x 10^-3 m/s2]
2. A muscle builder holds the ends of a massless rope. At the center of the rope, a 15-kg ball is hung. What is the tension in the rope if both angles θ are 4.5°. (The angles are under, respecting the horizontal line.) [Answer: 940N]
3. If the coefficient of kinetic friction, μk, between a block and the surface is .30 and the magnitude of the frictional force is 80N, what is the weight of the block? [Answer: 4.0]
4. A 250-N force is directed horizontally to push a 29-kg box up an inclined plane (27 degrees respect to the horizontal) at a constant speed. Determine the magnitude of the normal force, FN, and the coefficient of kinetic friction, µk. [Answer: 370N and .26]
5. A 2.0-N rock slides on a frictionless inclined plane. Which one of the following statements is true concerning the normal force that the plane exerts on the rock?
A) The normal force is zero Newtons.
B) The normal force is 2.0 N.
C) The normal force is greater than 2.0 N.
D) It increases as the angle of inclination, q, is increased.
E) The normal force is less than 2.0 N, but greater than zero Newtons. [Answer: E]
6. Two forces act on a 4.5-kg block resting on a frictionless surface as shown. What is the magnitude of the horizontal acceleration of the block? Link to image: http://img363.imageshack.us/img363/6591/picki0.jpg [Answer: 1.8 m/s2]
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