Other Physics Answers

Two uniform spheres, each of mass 0.260 𝑘𝑔, are fixed at points 𝐴 and 𝐵 (Figure 89). Find the magnitude and direction of the initial acceleration of a uniform sphere with mass 0.010 𝑘𝑔 if released from rest at point 𝑃 and acted on only by forces of gravitational attraction of the spheres at 𝐴 and 𝐵.

An 8.00-𝑘𝑔 point mass and a 12.0-𝑘𝑔 point mass are held in place 50.0 𝑐𝑚 apart. A particle of mass 𝑚 is released from a point between the two masses 20.0 𝑐𝑚 from the 8.00-𝑘𝑔 mass along the line connecting the two fixed masses. Find the magnitude and direction of the acceleration of the particle. 

A typical adult human has a mass of about 70 𝑘𝑔. (a) What force does a full moon exert on such a human when it is directly overhead with its center 378,000 𝑘𝑚 away? (b) Compare this force with the force exerted on the human by the earth.

Two uniform spheres, each with mass 𝑀 and radius 𝑅, touch each other. What is the magnitude of their gravitational force of attraction? 

Calculate the acceleration due to gravity at the surface of the moon. The moon’s radius is about 1.7 × 106 𝑚 and its mass is 7.4 × 1022 𝑘𝑔.

Calculate the centripetal acceleration of the earth in its orbit around the sun and the net force exerted on the earth. What exerts this force on the earth? Assume the earth’s orbit is a circle of radius 1.49 × 1011 m. 

Calculate the force of gravity on a spacecraft 12,800 𝑘𝑚 above the earth’s surface if its mass is 850 𝑘𝑔. 

The moon has a mass of 7.32 × 1022 𝑘𝑔 and a radius of 1,609.4 𝑘𝑚. Calculate the value of "𝑔" at the surface of the moon.

A radio-controlled model airplane has a momentum given by [(−0.75𝑘𝑔 ∙ 𝑚 𝑠 3 ⁄ )𝑡 2 + (3.0𝑘𝑔 ∙ 𝑚⁄𝑠)]𝑖̂+ (0.25𝑘𝑔 ∙ 𝑚 𝑠 2 ⁄ )𝑡𝑗̂. What are the 𝑥-, 𝑦-, and 𝑧-components of the net force on the airplane?

A hockey puck 𝐵 rests on a smooth ice surface and is struck by a second puck 𝐴, which was originally traveling at 40.0 𝑚/𝑠 and which is deflected 30.0 o from its original direction shown in Figure 2. Puck 𝐵 acquires a velocity of a 45.0 o angle to the original direction of 𝐴. The pucks have the same mass (Figure 79). a) Compute the speed of each puck after the collision. b) What fraction of the original kinetic energy of puck 𝐴 is dissipated during the collision?