Explanation:
The position vector r:

The velocity vector v:

The acceleration vector a:



Answer:
The workdone is 
Explanation:
The free body diagram is shown on the first uploaded image
From the question we are given that
The force is on the force gauge 
The distance that Magnus pulled the bus
Generally the workdone by the tension force on Magnus is


This negative sign show that is tension force is in the opposite direction to Magnus movement (i.e the movement of the bus )
Substituting value we have


Answer:
time required after impact for a puck is 2.18 seconds
Explanation:
given data
mass = 30 g = 0.03 kg
diameter = 100 mm = 0.1 m
thick = 0.1 mm = 1 ×
m
dynamic viscosity = 1.75 ×
Ns/m²
air temperature = 15°C
to find out
time required after impact for a puck to lose 10%
solution
we know velocity varies here 0 to v
we consider here initial velocity = v
so final velocity = 0.9v
so change in velocity is du = v
and clearance dy = h
and shear stress acting on surface is here express as
= µ 
so
= µ
............1
put here value
= 1.75×
× 
= 0.175 v
and
area between air and puck is given by
Area =
area =
area = 7.85 ×
m²
so
force on puck is express as
Force = × area
force = 0.175 v × 7.85 × 
force = 1.374 ×
v
and now apply newton second law
force = mass × acceleration
- force = 
- 1.374 ×
v = 
t = 
time = 2.18
so time required after impact for a puck is 2.18 seconds
B is the answer because it takes millions of years to form these fossil fuels and everyday we use way more than we can find we may have a surplus for now but we may run out sooner than some think