Answer:
The acceleration is 
and the distance covered is 97.17 m.
Explanation:
Given that,
Initial speed of an automobile, u = 60 km/hr = 16.67 m/s
Final speed of an automobile, v = 80 km/hr = 22.2 m/s
Time, t = 5 s
We need to find the acceleration of the car and the distance traveled in this 5 sec interval. Let a is the acceleration. Using the definition of acceleration as :
Let d is the distance covered. Using the third equation of motion to find it as follows :
So, the acceleration is and the distance covered is 97.17 m.
Explanation :
Speed of car, 
Kinetic energy of the car, 
Speed of car, 
Let 
is the kinetic energy of the car when it is moving with 100 km/h.
Initial velocity of both cars are 0. Using third equation of motion :
So, 
and 
t is same. So,
So, the braking distance at the faster speed is twice the braking distance at the slower speed.
<span>First law of thermodynamics. This conservation law states that energy cannot be created or destroyed but can be changed from one form to another. In essence, energy is always conserved but can be converted from one form into another. Like when an engine burns fuel, it converts the energy stored in the fuel's chemical bonds into useful mechanical energy and then into heat, or more specifically, the melting ice cubes. Yeast breaks down maltose into glucose to produce alcohol and Co2 in the fermentation process. This is a prime example of the 1st law of thermodynamics. No form of usable energy is really lost; it only changes from one form to another</span>
Ways to increase friction
- increase the area of contact
- increase the roughness of the contact materials
- dry up or take away any lubricant
- increase the pressure on the contact
