1. A [tex]\(24 \, \text{kg}\)[/tex] rock containing [tex]\(3,528 \, \text{J}\)[/tex] of potential energy rests upon the edge of a cliff. How tall is the cliff?

2. How much kinetic energy does a [tex]\(6 \, \text{kg}\)[/tex] cart have when moving at [tex]\(4 \, \text{m/s}\)[/tex]?

3. What is the mass of a bicycle moving at [tex]\(8 \, \text{m/s}\)[/tex] with a [tex]\(KE\)[/tex] of [tex]\(384 \, \text{J}\)[/tex]?



Answer :

Sure, I'll provide a detailed, step-by-step solution to each of the questions.

### Question 1: Height of Cliff

Given:
- Mass of the rock ([tex]\( m \)[/tex]) = 24 kg
- Potential energy ([tex]\( PE \)[/tex]) = 3528 J
- Gravitational acceleration ([tex]\( g \)[/tex]) = 9.8 m/s²

We need to find the height of the cliff ([tex]\( h \)[/tex]) using the formula for potential energy:
[tex]\[ PE = mgh \][/tex]

Rearranging the formula to solve for height ([tex]\( h \)[/tex]) gives:
[tex]\[ h = \frac{PE}{mg} \][/tex]

Substitute the given values:
[tex]\[ h = \frac{3528 \, \text{J}}{24 \, \text{kg} \times 9.8 \, \text{m/s}^2} \][/tex]

Calculate:
[tex]\[ h = 14.999999999999998 \, \text{m} \][/tex]
So, the height of the cliff is approximately 15 meters.

### Question 2: Kinetic Energy of Cart

Given:
- Mass of the cart ([tex]\( m \)[/tex]) = 6 kg
- Velocity of the cart ([tex]\( v \)[/tex]) = 4 m/s

We need to find the kinetic energy ([tex]\( KE \)[/tex]) using the formula:
[tex]\[ KE = \frac{1}{2}mv^2 \][/tex]

Substitute the given values:
[tex]\[ KE = \frac{1}{2} \times 6 \, \text{kg} \times (4 \, \text{m/s})^2 \][/tex]

Calculate:
[tex]\[ KE = 0.5 \times 6 \times 16 \][/tex]
[tex]\[ KE = 48 \, \text{J} \][/tex]
So, the kinetic energy of the cart is 48 Joules.

### Question 3: Mass of Bicycle

Given:
- Velocity of the bicycle ([tex]\( v \)[/tex]) = 8 m/s
- Kinetic energy ([tex]\( KE \)[/tex]) = 384 J

We need to find the mass of the bicycle ([tex]\( m \)[/tex]) using the rearranged formula for kinetic energy:
[tex]\[ KE = \frac{1}{2}mv^2 \][/tex]

Rearranging to solve for mass ([tex]\( m \)[/tex]) gives:
[tex]\[ m = \frac{2KE}{v^2} \][/tex]

Substitute the given values:
[tex]\[ m = \frac{2 \times 384 \, \text{J}}{(8 \, \text{m/s})^2} \][/tex]

Calculate:
[tex]\[ m = \frac{768}{64} \][/tex]
[tex]\[ m = 12 \, \text{kg} \][/tex]
So, the mass of the bicycle is 12 kg.

In summary:
1. The height of the cliff is approximately 15 meters.
2. The kinetic energy of the cart is 48 Joules.
3. The mass of the bicycle is 12 kg.