Answer- It decreases(C)
Reason- Using law of conservation of linear momentum,

where M- Speed of freight car,
v- Speed of car before coal is dumped into it
m-Mass of coal
V-Common velocity of car and coal
v1=0 m/s
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3. A freight car moves along a frictionless level railroad track at constant speed. The car...
A 6450-kg railroad car travels alone on a level frictionless track with a constant speed of 20.0 m/s . A 3850-kg load, initially at rest, is dropped onto the car. Part A What will be the car's new speed? Express your answer to three significant figures and include the appropriate units.
A 12100 kg railroad car is coasting on a level, frictionless track at a speed of 19 m/s when a 4790 kg load is dropped onto it. If the load is initially at rest, find the new speed of the car and the % change of the kinetic energy.
A 12100 kg railroad car is coasting on a level, frictionless track at a speed of 19.0 m/s when a 4790 kg load is dropped onto it. If the load is initially at rest, find the new speed of the car and the % change of the kinetic energy.
A railroad freight car, mass 15 000 kg, is allowed to coast along a level track at a speed of 3.0 m/s. It collides and couples with a 54 000-kg loaded second car, initially at rest and with brakes released. What percentage of the initial kinetic energy of the 15 000-kg car is preserved in the two-coupled cars after collision? Answer options below. A. 14% B. 18% C. 78% D. 22% E. 38%
Required information In the railroad freight yard, an empty freight car of mass m rolls along a straight level track at 1.20 m/s and collides with an initially stationary, fully loaded boxcar of mass 5.70m. The two cars couple together on collision. What is the speed of the two cars after the collision? m/s
In the railroad freight yard, an empty freight car of mass m rolls along a straight level track at 1.20 m/s and collides with an initially stationary, fully loaded boxcar of mass 5.20m. The two cars couple together on collision. A). What is the speed of the two cars after the collision? B). Suppose instead that the two cars are at rest after the collision. With what speed was the loaded boxcar moving before the collision if the empty one...
An empty freight train car of mass 10000 kg is rolling along a level of track at 2.00 m/ s . It collides with a loaded car of weight 1.96 * 10^5 n which is at rest . What is the speed of the train after the collision
A railroad car moves under a grain elevator at a constant speed of 3.2 m/s. 435 kg of grain drops into the car reducing its speed to 2.6 m/s. What is the mass of the railroad car?
a cart moves along a frictionless track on a rainy day. The rain falls straight down, and some of it lands in the open cart. The raindrops fall in such a way that they either land in the cart or do not hit it at all. There is no air resistance. Does the cart slow down, speed up, or maintains constant speed? Explain.
An open cart is travelling at constant speed on a level surface. A load of coal falls straight down into the cart. What happens to the speed of the cart after the coal falls into it? A. It stops. B. It speeds up. C. It slows down. D. It stays the same.