Mechanics | Relativity Answers

When a meteor falls on earth across the earth's atmosphere there acts 3 forces on it. 2 of them are the gravity and the upthrust. Mention the third force.

When a meteor falls on earth across the earth's atmosphere there acts 3 forces on it. 2 of them are the gravity and the upthrust. Mention the third force.

Two crates, one with mass 4.00 kg and the other with mass 6.00 kg, sit on the frictionless surface of a frozen pond, connected by a light rope. A woman wearing golf shoes (so she can traction on the ice) pulls horizontally on the 6.00 kg crate with a force F that gives the crate an acceleration of 2.50 m/s^2. a) What is the magnitude of the force F? b) What is the tension in the rope connecting the two crates?

Abbey and Mia are in the basement playing pool. On Abbey's recent shot, the cue ball was moving east at 82 cm/s when it struck the slower 5-ball moving in the same direction at 24 cm/s. The 5-ball immediately speeds up to 52 cm/s. Determine the post-collision speed of the cue ball in cm/s.

Bailey is on the tenth frame of her recent bowling competition and she needs to pick up the last pin for a spare and the first place trophy. She rolls the 7.39 kg ball down the lane and it hits the 1.41 kg pin head on. The ball was moving at 7.9 m/s before the collision. The pin went flying forward at 1.7 m/s. Determine the post-collision speed of the ball.

An 108.0 kg boy and a 61.1 kg girl, both wearing skates face each other at rest on a skating rink. The boy and girl push each other, sending her eastward with a speed of 3.09 m/s. Determine the final velocity of the boy. Neglect friction.

A bicycle has a momentum of 24 kg m/s. What momentum would the bicycle have if it had…

… twice the mass and was moving at the same speed?

Answer 1

… the same mass and was moving with one-half the speed?

Answer 2

… three times the mass and was moving with twice the speed?

Answer 3

… one-half the mass and was moving with twice the speed?

Answer 4

… the same mass and was moving with twice the speed?

Answer 5

… three times the mass and was moving with one-half the speed?

A child throws a 0.50 kg snowball at his friend at 12.0 m/s but the snowball lands on the ground in front of his friend.

The snowball is 1.3 m above the ground when it leaves the child’s hand.

(a) What is the (i) kinetic energy & (ii) potential energy of the snowball at the time of release?

(b) What is the total energy of the snowball (i) at the time of release & (ii) just before it hits the ground?

(c) What is the snowball’s kinetic energy just before it hits the ground in front of his friend?

(d) How fast is the snowball moving just before it hits the ground in front of his friend?

A toboggan carrying two children (total mass = 85 kg) reaches its maximum speed at the bottom of a hill, and then glides to a stop in 21 m along a horizontal surface.The coefficient of kinetic friction between the toboggan and the snowy surface is 0.11.

(a) Draw a FBD of the toboggan as it slows down, and calculate the magnitude of ALL the forces in the diagram.

(b) Calculate the acceleration of the toboggan.

(c) Calculate the work done on the toboggan by the friction on the snowy surface.Should the work be positive or negative?Explain.

A 2 kg rectangular thin plate has a length of 0.5 m and a width of 0.20. the moment of inertia

of the plate is 0.29 kg-m2

. Where is the location of the axis of rotation?