Explanation:
Given that,
Mass of the car, m = 710 kg
Speed of the car, v = 23 m/s
Drag force, F = 500 N
(a) Let P is the power is required from the car's engine to drive the car on the level ground. Power is given by :
(b) Let P is the power is required from the car's engine to drive the car on up a hill with a slope of 2 degrees.
At this slope, force will be, 
Total force will be :
Power is given by :
or
P = 17 kW
Answer:
dg= 942m
Explanation:
given the depth of the granite Us dg = 500m
time between the explosion t = 0.99s
the speed of sound in granite is Vg = 6000m/s
First of all calculate the time it takes the sound waves to travel down through the lake
Vw = dw/t1
t1 = dw/Vw
t1 = 500/1480
t1 = 0.338s.
Let dg be the depth of the granite basin, so the time it takes for the sound to travel down through the granite is t2 = dg/6000m/s......equation(1)
So the total time it takes to travel down to the oil surface will be
t1/2 = t1 + t2
t1/2= 0.338 + dg/6000.
since the reflection on the oil does not change the speed of sound, the sound will take travelling upto the surface the same time it takes to reach the oil
so; t = 2 t1/2
t1/2 = t/2 = 0.99s/2 = 0.495
Now insert into the values of t1/2 into the equation (1) and solve for dg;
we get 0.495 = 0.338 + dg/6000
dg = (0.495 - 0.338) x 6000
dg = 942m.
Answer:
Value that the spring constant k = 12Mg / h
Explanation:
According to 2nd law of Newton:
upward force of the spring= F
The weight of the elevator W = mg
F = Mg = M(5g)
==> F =6Mg.
As the spring is compressed to its maximum distance ie s,the maximum upward acceleration comes just , Hence
F =ks = 6Mg
==> s = 6Mg/k
We have gravitational potential energy turning into elastic potential of the spring as the elevator starts at the top some distance h from the spring, and undergoes a total change in height equal to h + s, so:
Mg(h+s) = 1/2ks2
And plugging in our expression for s:
Mg(h+6Mg/k)= 1/2k(6Mg / k)2
gh + 6M2g2/k = 1/2k(36M2g2 /k2)
Mgh +6M2g2/k = 1/2k(36M2g2 /k2)
gh + 6Mg2/k = 18Mg2 / k
gh = 12Mg2 / k
h = 12Mg / k
k = 12Mg / h
