Mechanics | Relativity Answers

The moon is 3.9 × 10⁵ km from Earth's center and 1.5 × 10⁸ km from the Sun's center. The masses of earth and the sun are 6.0 × 10²⁴ kg and 2.0 × 10³⁰ kg, respectively. Find the ratio of the gravitational fields due to Earth and the Sun at the center of the Moon.

The planet Saturn has about 100 times the mass of the earth and is about 10 times farther from the sun than the earth is. Compared to acceleration of the earth caused by the sun's gravitational pull, how great is the acceleration of saturn due to the sun's gravitation?

What is the angular velocity of a car whose tire radius is 0.300 meter when the car travels at a linear speed of 15 m/s?

A 50-N force is applied at the end of the wrench handle that is 24-cm long. The force is applied in a direction perpendicular to the handle as shown.

A. What is the torque applied to the nut by the wrench?

B. What would the torque be if the force were applied half-way up the handle instead of at the end?

A uniform rod of mass 2 kg and length of 2.0 m is pivoted about an axis perpendicular to the rod and 50 cm from its left end. Find the rotational inertia about this axis.

A plane flying at 80 m/s is uniformly accelerated at the rate of 2.0 m/s2. What is

the distance it will travel during a 10 s interval after acceleration begins?

 FA8: A plumb bob is dropped from the top of a 30.0 –ft building. Find: 

a. how long will it take the object to hit the ground?

 b. at what velocity will it hit the ground?

 c. how many meters shall have it fallen to have a velocity of 2.75 m/s?

 d. how many seconds shall have it fallen to travel 8.0 m?

 e. its displacement after 7.0 s

 f. how many seconds of its fall will it attain a velocity of 5.0 m/s

How far shall an object fall for it to have a velocity of 3.50 m/s? Neglect air resistance. 

A 170g air-track glider is attached to a spring. The glider is pushed in 9.40 cm

 and released. A student with a stopwatch finds that 8.00 oscillations take 19.0 s.

What is the spring constant?

Express your answer with the appropriate units.

Why F is only external force?