Question

An old building is being demolished by swinging a heavy metal ball from a crane. Suppose that such a 100 kg ball swings from a 20-m-long wire at speed 10m/s as the wire passes the vertical orientation. Assume the ball stops after sinking 1.5 m into the wall. What was the average force that the ball exerted on the wall?

Answer 1

`F_b=3333N`

Step-by-step explanation:

According to Newton's second law, we know that the average force that the ball exerts on the wall is equal to:

`F_b=m_ba_x`

Now, wa calculate the ball's acceleration, using the following kinetic equation:

`v_f^2=v_0^2+2a_xx`

The ball stops after sinking 1.5 m, so
`v_f=0`. Replacing and solving for
`a_x`:

`a_x=(-v_0^2)/(2x)\\a_x=(-(10(m)/(s))^2)/(2(1.5m))\\a_x=-33.33(m)/(s^2)`

Finally. we calculate the magnitude of the average force:

`F_b=100kg(33.33(m)/(s^2))\\F_b=3333N`