A toy car with a mass of 5.5 kg is moving horizontally over flat ground at a speed of 2.1 m/s. An unknown force then directly pushes the car for a distance of 3 meters, after which the car has a speed of 7.3 m/s. You may assume that air resistance and friction are both negligible. What was the magnitude of the unknown force

Respuesta :

Answer:

The magnitude of the unknown force is 44.8 N.

Explanation:

The force can be found with Newton's second law:                

[tex] F = ma [/tex]

Where:

m: is the mass of the toy car = 5.5 kg

a: is the acceleration

F: is the force =?

We can calculate the acceleration with the following kinematic equation:

[tex] v_{f}^{2} = v_{0}^{2} + 2ad [/tex]

Where:

[tex] v_{f} [/tex]: is the final speed = 7.3 m/s

[tex] v_{0} [/tex]: is the initial speed = 2.1 m/s

d: is the distance traveled = 3 m

Hence, the acceleration is:

[tex] a = \frac{v_{f}^{2} - v_{0}^{2}}{2d} = \frac{(7.3 m/s)^{2} - (2.1 m/s)^{2}}{2*3 m} = 8.15 m/s^{2} [/tex]

Finally, the magnitude of the force is:

[tex]F = ma = 5.5 kg*8.15 m/s^{2} = 44.8 N[/tex]                                  

Therefore, the magnitude of the unknown force is 44.8 N.

I hope it helps you!