Question

You push a 2.1 kg object on a table with 42 N of force. You are in contact with the box for 0.10 seconds. Ignoring friction, how fast is the box moving when you stop pushing?

(a) 2 m/s
(b) 4 m/s
(c) 8 m/s
(d) 16 m/s

Answer 1

The final velocity of the object after being pushed with a 42 N force for 0.10 seconds, with no friction, is 2.0 m/s. This is determined using the impulse-momentum theorem and the given values.

Step-by-step explanation:

The question asks for the final velocity of a 2.1 kg object after being pushed with 42 N of force for 0.10 seconds, assuming no friction. To find the final velocity, we can use the impulse-momentum theorem. The impulse exerted on the object is the product of the force and the time over which the force is applied. The change in momentum (Δp) is equal to the impulse (J).

First, we calculate the impulse:
J = F × t = 42 N × 0.10 s = 4.2 kg·m/s.

The initial velocity (u) of the object is 0 m/s because it's at rest. According to the impulse-momentum theorem:

Δp = J = m × Δv
4.2 kg·m/s = 2.1 kg × Δv

Now we solve for the change in velocity (Δv):
Δv = 4.2 kg·m/s / 2.1 kg = 2.0 m/s.

Therefore, the final velocity (v) of the object is 2.0 m/s, which is option (a).