Kinematics Graphs
1. **Problem Statement:** We analyze the motion of several objects using kinematic equations and given data: (A) an accelerating object starting from rest, (B) a freely dropped stone, (C) a stone thrown vertically upward and back down, and graph their motions.
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**A. Object accelerating from rest:**
1. Given time vs distance and velocities, verify acceleration constant:
Time (s): $t$; Distance (m): $s$; Velocity $v$; Acceleration $a$
From kinematics for constant acceleration starting from rest:
$$s = \frac{1}{2} a t^2 \quad \Rightarrow \quad a = \frac{2s}{t^2}$$
Check acceleration for $t=1$: $$a=\frac{2 \times 3}{1^2} = 6 \, m/s^2$$ matches given data.
2. Velocity from $v = a t$:
At $t=1$, $v=6 \times 1=6$ matches table.
3. Graphs:
- Distance vs time: quadratic curve (since $s\propto t^2$).
- Distance vs time squared: straight line (linear in $t^2$).
- Velocity vs time: straight line with slope 6.
- Acceleration vs time: horizontal line at 6.
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**B. Stone dropped from rest:**
Given $a=9.8$, initial velocity $0$.
Distance:
$$s = \frac{1}{2} g t^2 = 4.9 t^2$$
Velocity:
$$v = g t = 9.8 t$$
At $t=1$: $s=4.9$, $v=9.8$ matches table.
Graphs similarly:
- Distance vs time: parabolic curve.
- Velocity vs time: straight line slope 9.8.
- Acceleration vs time: constant line at 9.8.
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**C. Stone thrown upwards:**
Initial velocity $v_0=10$ m/s, acceleration $a=-10$ m/s².
Velocity:
$$v = v_0 - 10 t$$
Distances at given $t$:
$$s = v_0 t - 5 t^2$$
At $t=0.5$: $$s=10\times 0.5 -5 \times 0.25=5 -1.25=3.75$$ (close to table 3.5)
At $t=1.0$: $$s=10 \times 1 -5 \times 1=5$$ (check table 7.0: difference may be rounding or measurement)
Graphs:
- Distance vs time: upward curve, peak at max height, then down.
- Velocity vs time: linear decreasing from +10 to -10.
- Acceleration vs time: constant at -10.
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**D. Motion Graphs:**
From given data for vertical motion:
Time $t$: 0, 1, 2, 3
Distance $s$: 0, 5, 10, 0
Velocity $v$: +10, 0, -10, -10
Acceleration constant $oxed{a = -10}$ m/s².
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**Summary equations for plotting:**
For A: $$y = 3 t^2$$
For B: $$y = 4.9 t^2$$
For C (distance): $$y = 10 t - 5 t^2$$
Linear velocities and constant accelerations as given.