Answer:

To calculate the force applied by Tommy, we can use Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration.

Given:

Mass of the chair (m) = 28 kg

Final velocity (v) = 3 m/s

Time taken (t) = 5 s

First, we need to calculate the acceleration (a) using the formula:

a = (v - u) / t

Where:

v = final velocity = 3 m/s

u = initial velocity (which is 0 m/s since the chair starts from rest)

t = time taken = 5 s

a = (3 - 0) / 5

a = 3 / 5

a = 0.6 m/s²

Now, we can calculate the force (F) using the formula:

F = m * a

Where:

m = mass of the chair = 28 kg

a = acceleration = 0.6 m/s²

F = 28 * 0.6

F = 16.8 N

Therefore, Tommy applied a force of 16.8 Newtons to the chair.