Particle Motion 938074
1. **Problem statement:** A particle starts from rest and travels 64 m in 4 s under constant acceleration. We need to find:
- The time to travel half the total distance (32 m).
- The velocity at that time.
- The distance traveled in half the total time (2 s).
- The velocity at that time.
2. **Known values:**
- Initial velocity $u = 0$ (starts from rest)
- Total distance $s = 64$ m
- Total time $t = 4$ s
3. **Formula for distance under constant acceleration:**
$$ s = ut + \frac{1}{2}at^2 $$
Since $u=0$, this simplifies to:
$$ s = \frac{1}{2}at^2 $$
4. **Find acceleration $a$:**
$$ 64 = \frac{1}{2}a(4)^2 $$
$$ 64 = 8a $$
$$ a = 8 \text{ m/s}^2 $$
5. **Find time to travel half the distance (32 m):**
Using the same formula:
$$ 32 = \frac{1}{2} \times 8 \times t^2 $$
$$ 32 = 4t^2 $$
$$ t^2 = 8 $$
$$ t = \sqrt{8} = 2\sqrt{2} \approx 2.83 \text{ s} $$
6. **Velocity at $t = 2.83$ s:**
Velocity under constant acceleration:
$$ v = u + at = 0 + 8 \times 2.83 = 22.64 \text{ m/s} $$
7. **Distance traveled in half the total time (2 s):**
$$ s = \frac{1}{2} \times 8 \times (2)^2 = 4 \times 4 = 16 \text{ m} $$
8. **Velocity at $t = 2$ s:**
$$ v = 0 + 8 \times 2 = 16 \text{ m/s} $$
**Final answers:**
- Time to travel 32 m: $2\sqrt{2} \approx 2.83$ s
- Velocity at 32 m: 22.64 m/s
- Distance in 2 s: 16 m
- Velocity at 2 s: 16 m/s