You do an experiment with colliding cars on a low-friction track. Car 1 of mass 0.5 kg is moving in the direction at a speed of 2 m/s when it collides with Car 2 of mass 1.0 kg which is at rest. After the collision, Car 1 rebounds and moves to the right with a speed of 0.67 m/s. Define the system as Car 1.
A hockey puck (A) on a level air hockey table has mass = 0.100 kg and initial velocity m/s just before it collides with another hockey puck (B), which has mass kg. Just before the collision, puck B has a velocity m/s. The pucks stick together (because they are wrapped in velcro) upon colliding. What is the velocity of the system after the collision? Define the system as both hockey pucks, and assume that there is no net external force on the system.
Cart A has a speed of 1.5 m/s in the +x direction and Cart B is at rest when they collide. After the collision, Cart A rebounds in the –x direction with a speed of 0.75 m/s, and Cart B travels in the +x direction with a speed of 0.75 m/s. The mass of Cart A is 0.50 kg, and the mass of Cart B is 1.5 kg.
A 1200-kg truck travels in a straight line and has a speed 25 m/s in the +x direction when the driver hits the brakes. The truck slows down to 5 m/s in 10 s. Assume that the net force on the truck is constant.
A 500-kg Moon lander has a velocity of 10 m/s downward when it is a certain height above the ground. 1 minute later, it is 1 m from the ground and its speed is 0.5 m/s downward. Assume that the thruster on the lander fires upward with a constant force. Moon's gravitational field strength near its surface is 1.6 N/kg.
A 0.4-kg soccer ball is kicked from a location m (on the ground) with initial velocity m/s. The ball's speed is low enough that air resistance is negligible. Therefore, you can assume that the net force is constant. (Note: the +y direction is defined to be perpendicular to the ground and upward, and the x-z plane is the soccer field. t = 0 is defined to be the instant the ball leaves the foot.)
An electron of mass and initial speed in the –y direction enters a region between charged plates in which the force on the electron is constant, in the –x direction with a magnitude . After the electron travels 5 cm in the -y direction, it exits the region between the plates. At this instant when it exits, what is its momentum and how far has it deflected to the left from where it started?
A 20-kg girl rides on a merry-go-round. She is sitting near the edge of the merry-go-round and is rotating counterclockwise. The +z axis is defined to be perpendicular to the merry-go-round, and the +x and +y axes are in the plane of the merry-go-round. (See figures below.)
At , the velocity of the girl is m/s, and 0.15 s later, her velocity is m/s.
Ad a certain instant, the velocity of a 0.050-kg model rocket is , and all significant forces on the rocket are:
You push a 15-kg box across a somewhat smooth concrete floor as shown below.
You push with a force of 20 N at an angle, with respect to the horizontal, of . If the box moves in the +x direction with a constant speed, what is the force by the floor on the box? (Note: the gravitational force of Earth on the box is .)