Well, actually a heat engine using the Carnot cycle whose cold reservoir is maintained at 0 K could in principle be 100% efficient, even if the hot reservoir was merely at the ambient temperature. Since it costs no energy at all to maintain a heat reservoir at the ambient temperature as long as you have a perfect thermal connection to a large thermal capacitor like your swimming pool or a nearby aquifer you’d have built a perpetual motion machine.
Hi there!
We can begin by calculating the voltage drop across the 30 Ω resistor using the equation:
V = IR
V = Potential Difference (V)
I = Current (A)
R = Resistance (Ω)
Calculate the voltage. Recall that the current is CONSTANT across a series circuit.
V = 0.12 × 30 = 3.6 V
Voltage ADDS UP in a series, so:
Total V = V1 + V2
6 = 3.6 + V2
<u>V2 = 2.4V. The correct answer is A.</u>
ANSWER:
F(h)= 230 N is the horizontal force you will need to move the pickup along the same road at the same speed.
STEP-BY-STEP EXPLANATION:
F(h) is Horizontal Force = 200 N
V is Speed = 2.4 m/s
The total weight increase by 42%
coefficient of rolling friction decrease by 19%
Since the velocity is constant so acceleration is zero; a=0
Now the horizontal force required to move the pickup is equal to the frictional force.
F(h) = F(f)
F(h) = mg* u
m is mass
g is gravitational acceleration = 9.8 m/s^2
200 = mg*u
Since weight increases by 42% and friction coefficient decreases by 19%
New weight = 1+0.42 = 1.42 = (1.42*m*g)
New friction coefficient = μ = 1 - 0.19 = 0.81 = 0.81 u
F(h) = (0.81μ) (1.42 m g)
= (0.81) (1.42) (μ m g)
= (0.81) (1.42) (200)
= 230 N
