Answer:
a = 1 m/s²
Explanation:
given,
mass of the person = 60 Kg
Net External force exerted = 90 N
force of friction opposing the motion = 30 N
acceleration of the box = ?
Net force = External force applied - frictional force
Net force = 90 - 30
net force = 60 N
we know
F = mass x acceleration
60 = 60 x a
a = 1 m/s²
acceleration of the box is equal to a = 1 m/s²
Answer: 
Explanation:
The acceleration of the motorcycle is given by

where
v=24 m/s is the final velocity of the motorcycle
u=15 m/s is the initial velocity
t=3 s is the time taken
Substituting these numbers into the equation, we find

<u>Answer</u>
8. 2 Hz
9. 0.5 seconds
10. 20 cm
<u>Explanation</u>
<u>Q 8</u>
Frequency is the number of oscillation in a unit time. It is the rate at which something repeats itself in a second.
In this case, the spring bob up and down 2 times per second.
∴ Frequency = 2 Hz
<u>Q 9</u>
Period is the time taken to complete one oscillation.
2 oscillations takes 1 second
1 oscillation = 1/2 seconds.
∴ Period = 0.5 seconds
<u>Q 10</u>
Amplitude is the the maximum displacement of the spring.
In this case the spring bob up 20 cm. This is it's displacement.
∴ Amplitude = 20 cm
Endless movement between hot and cold will eventually mean the end of the universe. This law is about inefficiency, degeneration and decay. <u>The second law can be expressed in several ways, the simplest being that heat will naturally flow from a hotter to a colder body. At its heart is a property of thermodynamic systems called entropy.</u> Entropy basically means an increase in randomness. Hope this helps mate.