Chapter 19, Problem 49A

a.

To determine

To show :Gravitational potential energy is equal to 500 J.

Explanation of Solution

Given:

Height is given, $h=50\text{ m}$

Mass is of water, $m=1\text{ kg}$

Formula used:

  $PE=mgh$

Where, PE is gravitational potential energy, m is mass, g is acceleration due to gravity and h is height.

Calculation:

Acceleration due to gravity, $g=10{\text{ m/s}}^2$

Now, substituting the value of m , g and h and solve.

  $\begin{array}{l}PE=1\times 10\times 50\\ =500\text{ J}\end{array}$

Conclusion:

Therefore, it is clear that gravitational potential energy is 500 J.

b.

To determine

To show:Pressure at base of tower is $500000{\text{ N/m}}^2$ .

Explanation of Solution

Given:

Height is given, $h=50\text{ m}$

Mass is of water, $m=1\text{ kg}$

Formula used:

  $P=\rho gh$

Where, P is pressure, $\rho$ is density, g is acceleration due to gravity and h is height.

Calculation:

Acceleration due to gravity, $g=10{\text{ m/s}}^2$

Density of water, $\rho =1000{\text{ kg/m}}^3$

Now, substituting the value of $\rho$ , g and h and solve.

  $\begin{array}{l}P=1000\times 10\times 50\\ =500000{\text{ N/m}}^2\end{array}$

Conclusion:

Therefore, it is clear from the above calculation that pressure at the bottom is $500000{\text{ N/m}}^2$ .