Answer:
The coupled velocity of both the blocks is 1.92 m/s.
Explanation:
Given that,
Mass of block A, 
Initial speed of block A, 
Mass of block B, 
Initial speed of block B, 
It is mentioned that if the two blocks couple together after collision. We need to find the common velocity immediately after collision. We know that due to coupling, it becomes the case of inelastic collision. Using the conservation of linear momentum. Let V is the coupled velocity of both the blocks. So,

So, the coupled velocity of both the blocks is 1.92 m/s. Hence, this is the required solution.
Your body continues to move unless stopped by the seatbelt. An object in motion will remain in motion. Since your body was already moving it will continue to.
Potential energy can be found using this formula:
PE= m * g * h
where:
PE= potential energy
m=mass
g=gravitational acceleration constant (9.8 m/s^2)
h= height
So your answer is height because you also use the gravitational constant.
Answer:
7.6 s
Explanation:
Considering kinematics formula for final velocity as

Where v and u are final and initial velocities, a is acceleration and s is distance moved.
Making v the subject then

Substituting 8.8 m/s for u, 138 m for s and 2.45 m/s2 for a then

Also, v=u+at and making t the subject of the formula

Substituting 27.45 m/s for v, 8.8 m/s for u and 2.45 m/s for a then

Therefore, it needs 7.6 seconds to travel
a) since force = mass * acceleration
f= 900 * 0 (because constant speed = 0 acceleration)
similarly b) f = 0