Answer:
The boat's acceleration is 4 m/s²
Explanation:
This question seeks to test the knowledge of acceleration and how to calculate acceleration when the speed is provided. Hence, the formula for acceleration would be used here.
Acceleration (m/s²) = speed (in m/s) ÷ time (in seconds)
Acceleration = 80 m/s ÷ 20 secs
Acceleration = 4 m/s² or 4 ms⁻²
The boat's acceleration is 4 m/s²
Answer:

Explanation:
Given


Required
Determine the speed of B w.r.t A
The question implies that, we determine the relative velocity of B w.r.t A
Because both trains are moving towards one another, the required velocity is a
both trains:
This is shown below:



Answer:
The initial vertical velocity is zero, u = 0 m/s
Explanation:
Given;
height of the table, h = 0.55 m
horizontal distance traveled by the tennis, x = 0.12 m
Apply the following kinematic equation;
h = ut + ¹/₂gt²
where;
u is the initial vertical velocity = 0, since the tennis ball rolled off the edge of a table.
h = ¹/₂gt²
The time to fall from the vertical height is given by;

The initial horizontal velocity of the tennis is given by;
x = vₓt
vₓ = x / t
vₓ = (0.12) / (0.335)
vₓ = 0.358 m/s
Therefore, the initial vertical velocity is zero, u = 0 m/s and initial horizontal velocity, vₓ is 0.358 m/s
Answer:
Acceleration due to gravity will be 
Explanation:
We have given length of pendulum l = 55 cm = 0.55 m
It is given that pendulum completed 100 swings in 145 sec
So time taken by pendulum for 1 swing 
We have to find the acceleration due to gravity at that point
We know that time period of pendulum;um is given by

So 

Squaring both side


So acceleration due to gravity will be 