A railroad flatcar of weight 7840 N can roll without friction along a straight horizontal track. Initially, a man of weight 643 N is standing on the car, which is moving to the right with speed 25 m/s; see the figure. What is the change in velocity of the car if the man runs to the left so that his speed relative to the car is 4.0 m/s?

An Atwood's machine consists of two masses m₁ and m₂ joined by a light cord which passes over a pulley. Initially, the heavier mass is positioned a distance h above the floor. The masses are released from rest. At what speed are the masses moving when the heavier mass strikes the floor? Here m₁ = 4kg, m₂ = 6kg, and h = 3m. The cord is long enough so that the lighter mass does not reach the pulley. Devices like this are used in the construction of elevators. (3.4 m/s)

The experiment done in lab is repeated, using a ball that has unknown mass m. You plot your data in the form of f 2 versus M/L, with f in rev/s, M in kg, and L in m. Your data falls close to a straight line that has slope 6.69 m/(kg · s2). Use g = 9.80 m/s2 and calculate the mass m of the ball.

Two rail cars roll without friction on a track.  The rail cars have different masses.   The heavier car is at rest.  The lighter car is moving with speed v, hits the heavier car, and sticks to it.  The combined two-car system then moves with speed v/5.   What is the ratio of masses of the two cars?  Ratio = mass of heavier car / mass of lighter car.

A 10-m-long glider with a mass of 680 kg (including the passengers) is gliding horizontally through the air at 20 m/s when a 60 kg skydiver drops out by releasing his grip on the glider. What is the glider's speed just after the skydiver lets go?

A 719-N man stands in the middle of a frozen pond of radius 4.0 m. He is unable to get to the other side because of a lack of friction between his shoes and the ice. To overcome this difficulty, he throws his 1.2-kg physics textbook horizontally toward the north shore at a speed of 4.0 m/s. How long does it take him to reach the south shore?

Figure 1 The positive direction 1i 2i m1 m2 "The lab frame:" This track is not moving.

A puck of mass m=2 kg moves on a circle of radius r=0.5 meters, on a frictionless table. The puck is attached to an object of mass M=10 kg by a cord that extends through a hole on the table. Find the speed of the puck if the object is at rest. You may take g=10m/s². Select one: O a. 4/3m/s O b.5/2m/s O c. 5m/s O d. 25m/s O e. 4m/s

A hockey puck with mass 0.1 kg is at rest at the origin (x = 0) on the horizontal, frictionless surface of the rink. At time t = 0 a player applies a force of 0.2 N to the puck, parallel to the x-axis; she continues to apply this force until t = 2 5. (a) What is the speed of the puck at t = 2 s? Round your answer to 2 decimal places.

A tennis ball has a mass of 0.055 kg. A professional tennis player hits the ball hard enough to give it a speed of 52 m/s (about 117 miles per hour.) The ball moves toward the left, hits a wall and bounces straight back to the right with almost the same speed (52 m/s). As indicated in the diagram below, high-speed photography shows that the ball is crushed about d = 2.4 cm at the instant when its speed is momentarily zero, before rebounding. D Making the very rough approximation that the large force that the wall exerts on the ball is approximately constant during contact, determine the approximate magnitude of this force.