If an object is dropped, how fast will it be moving after #4s#?

Question

Emily Abbate · Accepted Answer

#39.2m/s#

If an object is dropped, the major force acting on it is gravity. We mostly ignore smaller variables like air resistance. The acceleration of gravity downwards is about #9.8ms^-2#.

Acceleration is how much velocity (#m/s#) changes by the second, so the units for acceleration are #(m/s)/s# or #m/s^2#, which is also written mathematically as #ms^-2#.

If we have four seconds of movement, then multiply that by the acceleration and it will give you the velocity.

#9.8m/s^2 * 4s = 39.2(m*s)/s^2 = 39.2m/s#

Elena Albarran · Answer

undefined The speed of an object dropped near the surface of the Earth can be calculated using the formula for free fall:

$$v = g \cdot t$$

where $v$ is the final velocity, $g$ is the acceleration due to gravity (approximately $9.8 \, \text{m/s}^2$), and $t$ is the time in seconds.

Substituting the values into the formula:

$$v = (9.8 \, \text{m/s}^2) \cdot (4 \, \text{s})$$

$$v = 39.2 \, \text{m/s}$$

Therefore, after 4 seconds, the object will be moving at a speed of $39.2 \, \text{m/s}$.