Mechanics | Relativity Answers

2. In a truck-loading station at a post office, a small 0.200-kg package is released from rest at

point A on a track that is one quarter of a circle with radius 1.60 m.

The size of the package is much less than 1.60 m, so the package can be treated as a particle. It

slides down the track and reaches point B with a speed of 4.80 m/s.

From point B, it slides on a level surface a distance of 3.00 m to point C, where it comes to rest.

(a) What is the coefficient of kinetic friction on the horizontal surface?

(b) How much work is done on the package by friction as it slides down the circular arc from A

to B?

jalissa who has a mass of 55 kg ran from the zombies to try to hide in the closet what is the force requeired to accelerate her at 5 m/s2

A box of mass 10 kg is pulled by a mass-less rope with a force of 40 N. The rope

makes an angle of 30 with the horizontal. Draw the free-body diagram showing

all forces on the box. Determine the acceleration of the box if the coefficient of

kinetic friction between the floor and the box is 0.2. Take   2 g 10 ms .

10. Ice hockey star Wayne Gretzky is skating at 13.0 m/s toward a defender,

who in turn is skating at 5.00 m/s toward Gretzkey shown in Figure

right. Gretzky’s weight is 756 N; that of the defender is 900 N.

Immediately after the collision Gretzky is moving at 1.50 m/s in hisoriginal direction. Neglect external horizontal forces applied by the ice

to the skaters during the collision. A) What is the velocity of the

defender immediately after the collision? b) Calculate the change in the

combined kinetic energy of the two players.

8. A 0.0450-kg golf ball initially at rest is given a speed of 25.0 m/s when

it is struck by a club. If the club and ball are in contact for 2.00 ms, what

average force acts on the ball? Is the effect of the ball’s weight during

the time of contact significant? Why or why not?

7. A 68.5-kg astronaut is doing a repair in space on the orbiting space

station. She throws a 2.25-kg tool away from her at 3.20 m/s relative to

the space station. With what speed and in what direction will she begin

to move?

two shuffleboard of equal mass,one orange and the other yellow,are involved in a elastic,glancing collision.the yellow disk is initially at rest and is struck by the orange disk moving with a speed of 5.00 m/s.after collision,the orange disk moves along a direction that makes an angle of 37.0 with its initial direction of motion.the velocities of the two disks are perpendicular after the collusion.determine the final speed of each disk

When a student steps on a bathroom scale inside an elevator that is at rest, the scale reads 490 N. When the elevator starts to move, the scale reads 425 N. Is the elevator moving up or down? What is its acceleration?