Question

A sled of mass 10 kg slides along the ice. it has an initial speed of 2 m/s but stops because of friction. How much work is done by friction?
A. 0 J
B. -20 J
C. -10 J
D. 20 J

Answer 1

Answer: The correct answer is option B.

Explanation:

Mass of the sled = 10 kg

Initial speed of the sled = 2 m/s

Kinetic energy of the sled = $\frac{1}{2}mv^2$

$\frac{1}{2}\times 10 kg\times (2 m/s)^2=20 Joules$

Work done by the sled = 20 joules

The work done by the friction will be in opposite direction and equal to the magnitude of the work done of the sled that - 20 J.

Hence, correct answer is option B.

Answer 2

Answer:-20

Explanation: