Answer:
B) Force of gravity
Explanation:
As it is the force which acts downward on the body towards the ground, it is clearly the force gravity represented by the arrow at A.
Answer:
The coefficient of kinetic friction 
Explanation:
From the question we are told that
The length of the lane is 
The speed of the truck is 
Generally from the work-energy theorem we have that

Here N is the normal force acting on the truck which is mathematically represented as
is the change in kinetic energy which is mathematically represented as
=>
=>

=> 
=> 
The two types of motion exerted in bicycle are:
1. rotary motion
2. linear motion
Sound waves actually travel much faster in water than air, but words and the direction of the noise are distorted.