Question 1: Speed Calculations

Speed is calculated using the formula:

$\text{Speed} = \frac{\text{Distance}}{\text{Time}}$

Part A: Car's Speed

Given:

• Distance traveled = 400 meters
• Time taken = 20 seconds

$\text{Speed} = \frac{400 \, \text{m}}{20 \, \text{s}} = 20 \, \text{m/s}$

Answer: The speed of the car is 20 meters per second (m/s).

Part B: Athlete's Speed

Given:

• Distance traveled = 1500 meters
• Time taken = 4 minutes = 4 × 60 = 240 seconds

$\text{Speed} = \frac{1500 \, \text{m}}{240 \, \text{s}} = 6.25 \, \text{m/s}$

Answer: The speed of the athlete is 6.25 meters per second (m/s).

Question 2: Final Velocity Calculations

To calculate the final velocity of a particle moving with uniform acceleration, we use the formula:

$v_f = v_i + a \cdot t$

Where:

• $v_f$ = final velocity
• $v_i$ = initial velocity (4 m/s)
• $a$ = acceleration (2 m/s²)
• $t$ = time

Part A: Final Velocity 1 Second Later

Given:

• Time $t = 1$ second

$v_f = 4 \, \text{m/s} + (2 \, \text{m/s}^2 \times 1 \, \text{s}) = 4 \, \text{m/s} + 2 \, \text{m/s} = 6 \, \text{m/s}$

Answer: The final velocity after 1 second is 6 meters per second (m/s).

Part B: Final Velocity 5 Seconds Later

Given:

• Time $t = 5$ seconds

$v_f = 4 \, \text{m/s} + (2 \, \text{m/s}^2 \times 5 \, \text{s}) = 4 \, \text{m/s} + 10 \, \text{m/s} = 14 \, \text{m/s}$

Answer: The final velocity after 5 seconds is 14 meters per second (m/s).

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Would you like more details or have any questions about these calculations?

Relative Questions

1. How would the speed change if the car traveled 800m in 40 seconds?
2. What would be the athlete's speed if the race was completed in 5 minutes instead of 4 minutes?
3. How does acceleration affect the final velocity over different time intervals?
4. What is the significance of uniform acceleration in motion?
5. How would you calculate the distance traveled by the particle after 5 seconds?

Tip:

Always ensure that the units of time and distance are consistent when calculating speed. Convert minutes to seconds if needed.