4. A string pendulum 1.12 m long has a bob with a mass of 200 g. (a) What is the tension in the string when the pendulum is at rest? (b) What is the tension at the bottom of the swing, if the pendulum is moving at 1.2 m/s?

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1. A 97 g ball bobbing up and down on the ocean as the waves roll by has a vertical position that can be described as a function of time by x(t) = cos(10t). What is the force on the ball at a time of 4.6 seconds? Note: The argument of the cosine function is in radians. Hint: Don't forget the sign of the force. F = 6.74 X√ N

6. The static coefficient of friction μs applies to an object of mass m placed on a platter that revolves about a vertical axis at frequency f. Derive an expression for the maximum distance r from the center of the platter at which the object can remain without sliding off the platter.

An astronaut lands on a foreign world and wants to measure the local gravitational field strength where he lands. He takes a 0.31m length pendulum and holds it 4 degrees from the vertical. He then releases the pendulum and measures that it takes 7.85 seconds for the pendulum to swing through 10 cycles of swing. What is the gravitational field strength on the planet?

1.A watch haneing from a chain swings back and forth every seconds. What is the frequency of its oscillations? Calculate answer to one decimal 2.In an experiment performed in a space station, a force of 13 N causes an object to have an acceleration equal to 4, 4 m/s What is the object's mass? Calculate answer to one decimal. 3.A person stands on a scale inside an elevator at rest. The scale reads 787 N. what is the person's mass? Calculate answer to one decimal. (use g=9.8 m/s^ 2 ) 4.A person stands on a scale inside an elevator at rest. The scale reads 800 N. The efevator accelerates upward at the rate of 1.3 m/s ^ 2 . What does the scale read then? Calculate answer to one decimal. ( use g=9.8 m/s^ 2 ) 5.A race car rounds a curve at 55 m/s The radius of the curve 363 m and the car's mass is 1,293 kg. What is the centripetal force acting on the car? Calculate answer to one decimal 6.A9 kg mass hangs from a rope. A force is applied to the rope so that the mass is accelerated upward at…

A 2.50-kg rock is attached at the end of a thin, very light rope 1.45 m long. You start it swinging by releasing it when the rope makes an 11° angle with the vertical. You record the observation that it rises only to an angle of 4.5° with the vertical after swings. (a) How much energy has this system lost during that time? (b) What happened to the “lost” energy? Explain how it could have been “lost.”