Point object is an expression that is used in Kinematics. It refers the object whose dimensions are ignored or neglected and is treated as a dot object to simplify the calculations. When the object is treated as a point object it means the whole mass is summed in one point, you can imagine it as a sphere which has the mass and the radius is 0...
Answer:
t1 = t2 + 3.02 V = 41.5
V t1 - 1/2 g t1^2 = V t2 - 1/2 g t2^2
Both stones reach the same height after the specified times
V (t1 - t2) = g/2 (t1^2 - t2^2) = g/2 (t1 - t2) (t1 + t2)
2 V / g = t1 + t2 = 2t1 + 3.02
t1 = V / g - 1.51 = 41.5 / 9.8 -1.51 = 2.72 s
t2 = t1 + 3.02 = 5.74 sec
Check:
41.5 * 2.72 - 4.9 * 2.72^2 = 76.6 m
41.5 * 5.74 - 4.9 * 5.74^2 = 76.8 m
Speed of second stone = 41.5 - 9.8 * 2.72 = 14.8 m/s
A force over distance is work the unite is joules
Well if you didn't you could make mistakes, which would lead ,in the best case, at a fail of the circuit , or if it goes out of control it could be dangerous
for example you have to know that the wires become hot and they loose their abbilitys as connecters(the hotter it will, the more energy you lose becouse the R will be bigger)
1 horsepower is equal to 746 W, so the power of the engine is
The power is also defined as the energy E per unit of time t:
Where the energy corresponds to the work done by the engine, which is
. Re-arranging the formula, we can calculate the time t needed to do this amount of work:
