Respuesta :

Answer:

4. a = 2 m/s² 5. m = 20 kg

Explanation:

4.

Mass of the book, m = 2kg

The net force acting on the book, F = 4 N

Let a is the acceleration of the book. We know that,

F = ma

Put all the values,

[tex]a=\dfrac{F}{m}\\\\a=\dfrac{4}{2}\\\\a=2\ m/s^2[/tex]

So, the acceleration of the book is equal to [tex]2\ m/s^2[/tex].

5.

Kinetic energy of the car, K = 4000 J

Speed of the car, v = 20 m/s

We need to find the mass of the car. The formula for the kinetic enregy is given by :

[tex]K=\dfrac{1}{2}mv^2\\\\m=\dfrac{2K}{v^2}\\\\m=\dfrac{2\times 4000}{(20)^2}\\\\m=20\ kg[/tex]

So, the mass of the car is equal to 20 kg.