Answer:
54mph
Explanation:
Speed is defined as the change in distance of a body with respect to time.
Let x be the speed of Eric on his way to the football game, if he used 11hours to the football game, his distance will be the product of his speed and time taken i.e
Distance = speed × time
Distance= x × 11
Distance = 11x... (1)
During his return journey, his speed increases by 12mph with a return drive in only 9hours i.e speed = x+12 and time is 9hours
Since distance = speed × time (return Journey)
Distance = (x+12)×9
Distance = 9x+84...(2)
Note that the distance to and fro the journey is the same as such we will equate equations 1 and 2 to get his initial speed "x" to have;
11x = 9x+84
11x-9x = 84
2x = 84
x = 42mph
This means that his initial speed on his way to the football game is 42mph. Since his speed increases by 12mph during his return drive, his return speed will be 42mph + 12mph which gives 54mph.
Answer:
a) V1=11.05m/s V2=92.07m/s V3=17.24m/s
b) KE = 16238.26J
Explanation:
For tangential speeds:
For the kinetic energy, it can be calculated as:
Where:
So,
KE=16238.26J
Answer:
77362.56 J
163730.28571 J
Explanation:
A = Area = 25 mm²
l = Length = 300 mm
K = Constant = 
= Heat transfer factor = 0.75
= Melting factor = 0.63
T = Melting point of low carbon steel = 1760 K
Volume of the fillet would be
The unit energy for melting is given by
Heat would be
Heat required to weld is 77362.56 J
Amount of heat generation is given by
The heat generated at the welding source is 163730.28571 J
Answer:
(d) Force of friction acts in solids, liquids and gases and opposes the motion with respect to each other.
A balloon expanding would count as work because it is moving and none of the others are. However, I think that James pedaling also works because at least he is using his leg muscles even though he's not moving. He is working because he is exercising himself and that count as working. I would chose James over all of them.
