a. How much force does an 80 kg astronaut exert on his chair while sitting at rest on the launch pad? b. How much force does the astronaut exert on his chair while accelerating straight up at $10 \mathrm { m } / \mathrm { s } ^ { 2 }$?

It takes the elevator in a skyscraper 4.0 s to reach its cruising speed of 10 m/s. A 60 kg passenger gets aboard on the ground floor. What is the passenger's apparent weight a. Before the elevator starts moving? b. While the elevator is speeding up? c. After the elevator reaches its cruising speed?

Each of 100 identical blocks sitting on a frictionless surface is connected to the next block by a massless string. The first block is pulled with a force of 100 N. a. What is the tension in the string connecting block 100 to block 99?

An astronaut's weight on earth is 800 N. What is his weight on Mars, where $g = 3.76 \mathrm { m } / \mathrm { s } ^ { 2 }$?

A 23 kg child goes down a straight slide inclined $38 ^ { \circ }$ above horizontal. The child is acted on by his weight, the normal force from the slide, and kinetic friction. a. Draw a free-body diagram of the child. b. How large is the normal force of the slide on the child?

A 6kg bucket of water is being pulled straight up by a string at a constant speed. I determined that the tension on the string was F = ma F = (6kg * 9.8 m/s2) , F = 58.8 N Now its asking At a certain point the speed of the bucket begins to change. The bucket now has an upward constant acceleration of magnitude 3 m/s2. What is the tension in the rope now? The correct answer was "about 78N" then Now assume that the bucket has a downward acceleration, with a constant acceleration of magnitude3 m/s2. Now what is the tension in the rope?

A 1500 kg car is traveling along a straight road at 20 m/s. Two seconds later its speed is 21 m/s. What is the magnitude of the net force acting on the car during this time?

two children fight over a 200 g stuffed bear. The 25 kg boy left with a 17 N force. Ignore all other forces on the bear (such as its weight). a. At this instant, can you say what the velocity of the bear is? If so, what are the magnitude and direction of the velocity? b. At this instant, can you say what the acceleration of the bear is? if so what are the magnitude and direction of the acceleration?

A 4000 kg truck is parked on a $7.0 ^ { \circ }$ slope. How big is the friction force on the truck?

Can an object have a speed of zero while it has an acceleration that is not zero? Explain.

For each of the following sentences, choose the correct word or words in parentheses.

EXAMPLE: After practicing law for (a while, awhile), Mr. Milano decided that he would rather be a teacher. a while

Some pets (ain't , aren't) suited for life in a small apartment.

For the following quantities, indicate which is a scalar and which is a vector: your average velocity while running.

For each of the following sentences, choose the correct word or words in parentheses.

EXAMPLE: After practicing law for (a while, awhile), Mr. Milano decided that he would rather be a teacher. a while

Everyone I know likes peanut butter (accept, except) you.

Write an inequality for each sentence. While shopping, Abby spent no more than $50.