Gravity Physics Example 3

Follow the full solution, then compare it with the other examples linked below.

easy

A ball is dropped from rest near Earth's surface. How fast is it going after

3 \text{ seconds}

? Ignore air resistance and use

g = 9.8 \text{ m/s}^2

1
Gravity provides a constant downward acceleration of $g = 9.8 \text{ m/s}^2$ . The ball is dropped, so initial velocity $v_0 = 0$ .
2
Apply the kinematic equation for velocity: $v = v_0 + gt$ .
3
Substitute values: $v = 0 + 9.8 \times 3 = 29.4 \text{ m/s downward}$

Answer

v = 29.4 \text{ m/s downward}

Near Earth's surface, gravity accelerates all objects equally at

g \approx 9.8 \text{ m/s}^2

regardless of mass, assuming no air resistance.

About Gravity

The universal attractive force between any two objects with mass, decreasing with the square of distance.

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