Answer:
1. 3 
2. 1.5
3. 3 seconds
4. 0
5. 2.2 seconds
Explanation:
(1)
From v= u + at where v is final velocity, u is initial velocity, a is acceleration and t is time.
Making a the subject we have
Substituting u=0 since it’s at rest, v=30m/s and t=10 seconds
a = 
(2)
From v= u + at where v is final velocity, u is initial velocity, a is acceleration and t is time.
Making a the subject we have
Substituting u=10m/s, v=22m/s and t=8 seconds
a = 
(3)
From v= u + at where v is final velocity, u is initial velocity, a is acceleration and t is time.
Making t the subject we have
Substituting u=0m/s since at rest, v=15m/s and a=5 
= 
(4)
When initial and final velocity are constant, there’s no acceleration as proven below
From v= u + at where v is final velocity, u is initial velocity, a is acceleration and t is time.
Making a the subject we have
Substituting u=20 since it’s at rest, v=20m/s and t=10 seconds
a = 
(5)
From v= u + at where v is final velocity, u is initial velocity, a is acceleration and t is time.
Making t the subject we have
Substituting u=9m/s since at rest, v=0m/s and a=-4.1
= 
