An empty train car of mass 2.0 x 104 kg coasts along at 10 m/s. A ...

[cookcarl]

An empty train car of mass 2.0 x 104 kg coasts along at 10 m/s. A 3000-kg boulder is suddenly dropped vertically into the car. Find the speed of the car immediately after the boulder is dropped in.
 
  What will be an ideal response?

Question 2

Three cars (car L, car M, and car N) are moving with the same speed and slam on their brakes. The most massive car is car L, and the least massive is car N.
 
  If the tires of all three cars have identical coefficients of kinetic friction with the road surface, for which car is the amount of work done by friction in stopping it the greatest? A) The amount of work done by friction is the same for all cars.
  B) Car L
  C) Car M
  D) Car N

[wilsonbho]

Answer to Question 1

8.7 m/s

Answer to Question 2

B

[cookcarl]

Excellent

[mohan]

Gracias!