Science Homework Help

1) A luge and its rider, with a total mass of 170 kg, emerge from a downhill track onto a horizontal straight track with an initial speed of 53 m/s. Draw a diagram.

1. If a force slows them to a stop, what is the change in total kinetic energy for the luge and ride?

1. If a force slows them to a stop at a constant rate of 3.5 m/s², what magnitude F is required for the force, what is coefficient of kinetic friction of the track?

1. What distance d do they travel while slowing?

4) In figure 8-42, a block of mass m = 12 kg is released from rest on a frictionless incline of angle θ= 30^o. Below the block is a spring that can be compressed 2.0 cm by a force of 270 N.

DRAW THE FIGURE

The block momentarily stops when it compresses the spring by 5.5 cm.

1. What is the spring constant?

1. How far does the block move down the incline from its rest position to this stopping point?

1. What is the speed of the block just as it touches the spring?

5) A 0.30 kg softball has a velocity of 15m/s at an angle of 35^o below the horizontal just before making contact with the bat.

1. What is the magnitude and direction of the change in momentum of the ball while in contact with the bat if the ball leaves with a velocity of 20m/s, vertically downward?

1. If the ball is in contact with the bat for 2.5 msec, what is magnitude and direction of average force on the softball?