Let's break down each question using the relevant formulas.
Question 1
Given:
- Power (P) = 25 watts
- Work (W) = 5000 Joules
- Time (t) = ?
To find t, we use the formula: \[ P = \frac{W}{t} \] Rearranging gives us: \[ t = \frac{W}{P} \] Substituting the values: \[ t = \frac{5000 \text{ J}}{25 \text{ W}} = 200 \text{ seconds} \]
Answer: 200 seconds
Question 2
Given:
- Work (W) = 720 Joules
- Power (P) = 90 watts
Using the same formula: \[ t = \frac{W}{P} \] Substituting the values: \[ t = \frac{720 \text{ J}}{90 \text{ W}} = 8 \text{ seconds} \]
Answer: 8 seconds
Question 3
Given:
- Weight of the box (Force, F) = 10 Newtons
- Distance (d) = 20 meters
- Time (t) = 30 seconds
First, calculate work using: \[ W = F \cdot d = 10 \text{ N} \cdot 20 \text{ m} = 200 \text{ Joules} \] Now, use power formula: \[ P = \frac{W}{t} \] Substituting the values: \[ P = \frac{200 \text{ J}}{30 \text{ s}} \approx 6.67 \text{ watts} \]
Answer: 6.67 watts
Question 4
Given:
- Power (P) = 170 watts
- Time (t) = 20 seconds
Using the power formula again: \[ W = P \cdot t \] Substituting the values: \[ W = 170 \text{ W} \cdot 20 \text{ s} = 3400 \text{ Joules} \]
Answer: 3,400 J
Question 5
Given:
- Work (W) = 500 Joules
- Time (t) = 25 seconds
Power calculation: \[ P = \frac{W}{t} \] Substituting the values: \[ P = \frac{500 \text{ J}}{25 \text{ s}} = 20 \text{ watts} \]
Answer: 20 watts
Summary of Answers:
- 200 seconds
- 8 seconds
- 6.67 watts
- 3,400 J
- 20 watts
1 answer