A ball slips from Jada's hand and falls straight toward the floor. Which force pulls the ball downward after it is released?

Milo slides a book across his desk, and it slows down before stopping. Which force between the book and desk changes its motion?

A rider squeezes the hand brakes, and the bicycle slows as pads rub the wheel. Which force helps slow the bicycle?

A student lifts a backpack and says it feels heavy. Which force is pulling the backpack toward Earth?

A soccer ball rolls to the right across thick grass and slows down. In which direction does friction from the grass push on the ball?

Raindrops fall from a cloud. Gravity pulls them down, but a force from the air pushes against them so they do not keep speeding up. What is this force?

A student presses a classroom door, and the door swings open. What kind of force did the student use on the door?

Two teams tug on opposite ends of a rope during a game. What kind of force does each team apply to the rope?

A skateboard starts rolling faster down a smooth ramp without anyone pushing it. Which force makes it speed up?

A runner's shoes grip the track so the runner can push off without slipping. Which force helps the shoes grip?

A pencil rolls off a desk and falls. In which direction does gravity pull the pencil?

A sled slows quickly on dry grass but glides longer on icy snow. Which force explains the difference in how far it moves?

Earth pulls an apple downward before the apple touches the ground. Did the apple and Earth need to touch for this force?

A student pushes a cart across the room with both hands. Did the student and cart need to touch for this force?

A tire rubs against the road as a car stops at a crosswalk. Did the tire and road need to touch for this force?

Two magnets pull toward each other with a small gap between them. Did the magnets need to touch for this force?

Gravity from Earth keeps the Moon moving in its path around Earth. How does this force act on the Moon?

A child pulls a wagon by holding its handle. Did the child and wagon need to touch for this force on the wagon?

A foot kicks a resting ball, and the ball rolls away. Did the foot and ball need to touch for the kick?

A jumper leaves a diving board and is pulled downward toward the pool. How does gravity act on the jumper?

Brake pads press against a spinning wheel and make it slow down. Did the pads and wheel need to touch for the force?

Two magnets push away from each other while a gap remains between them. Did the magnets need to touch for this force?

A toy car rolls down a ramp covered with wax paper instead of rough cloth. What will the smoother surface most likely do?

A block is pulled across sandpaper instead of a smooth tabletop. How will the rougher surface most likely affect the block?

A squeaky door hinge moves more easily after a drop of oil is added. What did the oil most likely change?

A student wears rubber-soled shoes on a wet gym floor. How can the rubber soles help the student move safely?

A suitcase is hard to drag when its bottom slides on the floor, but easier after wheels are added. What did the wheels do?

A bike with deep tire treads moves better on a muddy path than a bike with smooth tires. What do the treads increase?

A sled moves from packed snow onto smooth ice. With the same push, what will the lower-friction ice most likely do?

A soccer player changes from smooth shoes to cleats before playing on grass. How do cleats help the player push off?

A toy car rolls down a wooden ramp, then down the same ramp covered with carpet. What will the carpet most likely do?

A climber dries wet hands before climbing a rope. How does drying the hands help?

With the same push, a box stops sooner on carpet than on tile. What does this observation show?

A shoe sole becomes smooth after months of use, and the wearer slips more often. What does this show about the worn sole?

A cyclist skids to a stop on a cool, cloudy evening, and the tire leaves a dark mark. Right after, the tire rubber feels warm. What made it warm?

Students walk carefully on an icy sidewalk because their shoes slide easily. What does this show about ice?

A catcher wears rough gloves so a fast ball is easier to hold. What does this show about friction?

A block slides only when a sandpaper ramp is tilted more steeply than a smooth ramp. What does this show about sandpaper?

After rollers are placed under a heavy board, students move it across the floor more easily. What does this evidence show?

A dropped rock and a dropped leaf both move downward, even though one falls faster. What force do both objects show?