A 2.0 kg block of ice with a speed of 8.0 m/s makes an elastic collision with another block of ice that is at rest. The first block of ice proceeds in the same direction as it did initially, but with a speed of 2.0 m/s. What is the mass of the second block? (Hint: Use the conservation of kinetic energy to solve for the second unknown variable.)

6kg

Explanation:

According to conservation of kinetic energy

m1u1+m2u2 = (m1+m2)v

m1 and m2 are the masses of the bodies

u1 and u2 are the initial velocities

v is the final velocity

Given

m1 =2kg

u1 = 8.0m/s

m2 = ?

u2 = 0m/s (second ice at rest)

v = 2.0m/s

Substitute into the formula

2(8)+m2(0) = (2+m2)(2)

16+0 = 4+2m2

16-4= 2m2

12 = 2m2

m2 =12/2

m2 = 6kg

Hence the mass of the second block is 6kg

real, smaller and upside-down.   so the answer should be b.

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.