calculate the train's final speed and energy lost with these numbers.  A train car hits a three-car train; together, it becomes a four-car train. The mass of each train car is 40*103 kg. The initial speed of the single car is 3.3 m/s. The initial speed of the three-car train is 1.8 m/s.

If a bullet of mass 8.7 g hits a block of wood of mass 5.212 kg and the bullet and wood swing up to a maximum height of 6.2 cm, what is the initial speed of the bullet

A tennis ball bouncing on a hard surface compresses and then rebounds. The details of the rebound are specified in tennis regulations. Tennis balls, to be acceptable for tournament play, must have a mass of 57.5 g. When dropped from a height of 2.5 m onto a concrete surface, a ball must rebound to a height of 1.4 m. During impact, the ball compresses by approximately 6 mm. If the ball accelerates uniformly when it hits the floor, what is its approximate acceleration as it comes to rest before rebounding?A. 1000 m/s2         B. 2000 m/s2C. 3000 m/s2         D. 4000 m/s2

Doing some physics homework and am kind of stumped here!

It is a sunny day, and we have decided to do lab outside instead of staying cooped up. Ceylani goes to the top of Jordan Hall, and throws a ball of mass 4.87 kg down from the top of Jordan which is 124 m tall. Her lab partner, Tray, is waiting at the bottom to collect the ball and return it, for more data trials. The ball has a speed of 3.8 m/s when Ceylani throws it straight down. What is the speed of the ball as it reaches the ground? Your Answer: units Answer

A mass of 700 kg moving at a speed of 36 km/h collides with a horizontally mounted spring of spring constant 6.26*10^3 N/m, what is the maximum compression (meters) of the spring?

Assume that the force of a bow on an arrow behaves like the spring force. In aiming the arrow, an archer pulls the bow back 48 cm and holds it in position with a force of 163 N. If the mass of the arrow is 51 g and the "spring" is massless, what is the speed of the arrow immediately after it leaves the bow? v=v=  m/s A boy throws a ball of mass 0.2 kg straight upward with an initial speed of 22 m/s When the ball returns to the boy, its speed is 17 m/s How much work does air resistance do on the ball during its flight? W=W= J (give the absolute value, rounded to one decimal place)

A 31.0-kg skateboarder rides on a 10.0-kg skateboard at 5.7 m/s on a level road before jumping into air with a speed of 10.0 m/s against the ground in the direction of 27.0◦ above the forward, horizontal direction to leave the skateboard. Ignore air resistance and the friction between the road and skateboard.   What is the maximum height that the skateboarder can reach? (A) 1.05 m; (B) 1.25 m; (C) 1.45 m; (D) 1.65 m; (E) 1.85 m.   What is the speed of the skateboard on the ground after the jump? (A) 3.85 m/s; (B) 4.05 m/s; (C) 4.25 m/s; (D) 4.45 m/s; (E) 4.65 m/s.   What is the minimum work done by the skateboarder to make the jump? (A) 994J; (B) 974J; (C) 954J; (D) 934J; (E) 914J.

You wake up one morning to find yourself in a strange room with opaque walls, and no visible doors or windows. You decide to do some experiments to find out more about your strange situation. Your own body mass is 50.1 kg. You pick up an object and drop it from rest, starting at a height of 1.97 meters above the floor, and it hits the floor 0.380 seconds later. You can ignore air resistance. Based on the outcome of this experiment, when you step on the scale provided for you, what weight will it register for your body?     684 N     911 N     1,367 N     491.5 N

Gayle runs at a speed of 3.65 m/s and dives on a sled, initially at rest on the top of a frictionless snow-covered hill. After she has descended a vertical distance of 5.00 m, her brother, who is initially at rest, hops on her back and together they continue down the hill. What is their speed at the bottom of the hill if the total vertical drop is 15.0 m? Gayle's mass is 48.0 kg, the sled has a mass of 5.45 kg and her brother has a mass of 30.0 kg. m/s