Answer:
A. Heat flows from an object at higher temperature to an object at lower temperature
Explanation:
The option A obeys the 2nd law of thermodynamics. The heat will flow from the object at higher temperature to the object at Lower temperature till they reach an equilibrial state.
Heat doesn’t necessarily flow from an object with higher thermal energy to an object with lower thermal energy because an object has a higher thermal energy when it’s mass is more than the other. This makes B wrong.
C is wrong because heat moves from an object with higher temperature to objects with Lower temperature regardless of the state of matter.
Explanation:
Work is the dot product of the force and displacement vectors.
W = F · d
In other words, it is the force times the parallel component of the distance.
W = F d cos θ, where θ is the angle between the force and distance.
Answer:
15.7 m
Explanation:
m = mass of the sled = 125 kg
v₀ = initial speed of the sled = 8.1 m/s
v = final speed of sled = 0 m/s
F = force applied by the brakes in opposite direction of motion = 261
d = stopping distance for the sled
Using work-change in kinetic energy theorem
- F d = (0.5) m (v² - v₀²)
- (261) d = (0.5) (125) (0² - 8.1²)
d = 15.7 m
Answer:
4. 7.59276
Explanation:
Add up the x components:
Aₓ + Bₓ + Cₓ = 5 − 1.6 + 2.4 = 5.8
Add up the y components:
Aᵧ + Bᵧ + Cᵧ = -2.4 + 3.3 + 4 = 4.9
Use Pythagorean theorem to find the magnitude:
√(x² + y²)
√(5.8² + 4.9²)
√57.65
7.59276
