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.