You accidentally leave a cup of coffee on the horizontal roof of your car before driving on the level roads of your city. That cup is most likely to fall of the roof when your car is [neglect effects due to the air]

The ball that you throw to your friend travels in an arc, first rising to peak height and then descending. While the ball isn't touching anything and neglecting effects due to the air, when does the ball have the largest acceleration?

You are standing in the middle of a bus that is moving forward at constant velocity. You accidentally drop a bottle of salad oil on the floor and it breaks. Suddenly, the oily floor cannot exert any frictional forces on your feet. Nothing else is touching you, so you

Your restaurant table has a Lazy Susan, a freely rotating circular platform used to move food dishes around the table. The empty platform responds easily to a gentle torque. How does the platform respond to that same torque once there are food dishes on the platform?

A building has two balconies, one twice as high above you as the other. When a ball is dropped from the lower balcony reaches your hand, it is traveling 10 meters-per-second (about 22 miles-per-hour). When that ball is dropped from the upper balcony and falls twice as far, how fast is it traveling when it reaches your hand? [neglect any effects due to the air.]

A sheet of paper is lying flat on a horizontal table. There are several coins sitting motionless on the paper. You pull the paper suddenly toward the right and the coins barely move. The coins remain almost in place because

To win a huge stuffed bear at the county fair, all you have to do is toss a US quarter coin toward a smooth immovable glass plate and have the quarter remain on the plate. This task is surprisingly difficult because the coins keep bouncing off the plate and onto the ground. What prevents the coin from landing on the plate and stopping completely?

You get on your bicycle near the top of a long, smooth hill. After a moment of motionlessness, you start rolling downhill faster and faster. You did not use the pedals, so what caused the bicycle wheels to start turning?

You are riding a store's escalator and are currently moving from the first floor to the second floor at a constant velocity. In which direction is the escalator pushing on you?

You are swinging back and forth on a swing at the local playground. As you swing forward and pass directly below the supporting pivot, you feel heavier than normal. Your increased apparent weight is due to

A basketball basket is mounted on a rigid, immovable backboard. A player can bounce the basketball off the backboard on its way to the basket. When the basketball hits the backboard and rebounds, what conserved physical quantities does the basketball transfer to the backboard?

You board a motionless bus at a bus stop. You stand on your skateboard in the middle of the bus. As the bus accelerates forward, you find yourself shifting toward the back of the bus. From the perspective of a person standing motionless at the bus stop, what is your velocity as you shift?

The ball that you throw to your friend travels in an arc, first rising to peak height and then descending. While the ball isn't touching anything and neglecting effects due to the air, when does the ball have the smallest speed?

You are in a motionless elevator at the top floor of a tall building. There is a spring scale under your feet, currently correctly reporting your weight. You press a button and the elevator starts downward, moves steadily through the middle floors, and soon stops at the ground floor. What values does the scale report during that trip?

A melon is sitting at equilibrium in the weighing basket of a grocery store spring scale. You lift the melon upward slightly and release it. As the melon bounces up and down, the melon is accelerating downward whenever

A dog and a cat jump horizontally off a wall at the same moment and soon land on the level horizontal field that extends outward from the base of the wall. The dog weighs twice as much as the cat, but the dog was moving forward horizontally twice as fast as the cat when the two animals left the wall. In this situation,

A small tree behaves like a spring when it is bent away from equilibrium. When the wind exerts a 100-newton force on the tree, the tree bends 10 centimeters away from equilibrium. How far does the tree bend then the wind exerts a 200-newton force on the tree?

You must move a wagon full of library books from the first floor to the second floor. You can lift the wagon straight up a ladder or you can pull it uphill along a ramp. The ramp's surface is 4 times as long as the ladder. Compared to the work you do on the wagon lifting it up the ladder to the second floor, the work you do on the wagon pulling it uphill along the ramp to the second floor is

You are dropping coins into a wishing well. You drop each coin from rest and it falls to the water 9.8 meters below your hand. Assuming the acceleration due to gravity is 9.8 meters-per-second², how long does it take each coin to drop from your hand to the water? [neglect any effects due to the air.]

You purchase a 1-kilogram bag of flour and take it to testing laboratory. Sure enough, the flour's mass is 1.0 kilograms and its weight is 9.8 newtons (about 2.2 pounds). Your astronaut friend takes the flour to the moon, where another testing laboratory examines it. They find that the flour's mass is

In baseball, the pitcher throws the baseball toward the batter and the batter swings a bat forward to hit the oncoming ball. In which of the following cases will the baseball have the fastest forward speed after being hit by the bat?

You drop a bouncy ball straight downward onto a rigid, immovable floor. The ball bounces off the floor and rises about 70% of the way to your hand. When the ball is at its lowest height (lowest altitude) during the bounce, what are its velocity and acceleration?

You are having trouble unscrewing the lid of a jar of pickles. You attach a kitchen gadget to the lid, giving you a long handle to grip (see figure below). How should you push the handle to produce the largest torque in the direction that unscrews the lid and opens the jar?

You are involved in a game of tug-o-war with a plastic rope. The two teams are pulling on opposite ends of the rope. While your team holds your end of the rope motionless, the opposing team stretches their end of the rope toward them and the rope breaks. Breaking the rope required energy and that energy was provided by

You raise a grocery cart upward by pushing it along a ramp at a constant uphill velocity. If the cart's altitude increases by 5 meters as it travels 20 meters along the ramp's surface (see figure below), what is the amount of the uphill force you are exerting on the cart? [neglect friction or air effects]

You are a passenger in a car that is moving forward on level pavement. The driver brakes suddenly to avoid hitting a squirrel. As the car screeches to a stop, why does the distance between your head and the car's windshield (front window) suddenly decrease?

In an amusement park ride, you stand inside a hollow cylinder with your back against the wall of that cylinder. The cylinder is soon spinning rapidly at a constant angular velocity and you feel yourself pressed tightly against the wall. What is true about your motion?

A car traveling at 60 mph veers off the road and hits a tree. The car stops immediately. Fortunately, the airbag inflates and the driver comes to a stop in the airbag instead of coming to a stop on the steering wheel. Hitting the airbag rather than the steering wheel saves the driver's life because the driver

You step off a ledge and drop straight down onto a springy trampoline. You dent the trampoline deeply during your impact and then rebound high above the trampoline. When during your descent (the downward part of your motion) do you have the greatest downward velocity?

You're at the lake and watch two children jump off a dock. They jump at the same time and at the same speed, but the girl jumps mostly upward while the boy jumps mostly forward. After they leave the dock,