Answer:
4. To the east
Explanation:
Friction forces always act in the opposite direction that an object tends to move in. In this case, when the truck accelerates to the east, the crate tends to move to the west due to inertia (the tendency for an object to remain at rest or at constant speed). In order to stop the crate from moving, there needs to be a friction force to the east.
Answer:
Explanation:
V = 100sin(ωt) + 150cos(ωt)
let x = ωt
V = 100sin(x) + 150cos(x)
a maximum or minimum will occur when the derivative is zero
V' = 100cos(x) - 150sin(x)
0 = 100cos(x) - 150sin(x)
100cos(x) = 150sin(x)
100/150 = sin(x)/cos(x)
0.6667 = tan(x)
x = 0.588 rad
V = 100sin(0.588) + 150cos(0.588)
V = 180.27756
as the maximum will not occur until ωt = 0.588 radians, for a cosine function we subtract that amount as a phase angle φ
V = 180.3 cos(ωt - 0.588)
or as a sine function, the phase angle lags the cosine by a difference of π/2
V = 180.3sin(ωt - (0.588 - π/2)
V = 180.3sin(ωt + 0.983)
Force can be expressed as the time-rate change of momentum
Mathematically, Force = Change in momentum/change in time
Change in momentum = m(10.1-18.9) = -0.2024
Force = -2024/5.4 = -375N(approx)
The significance of the '-' sign is that the direction of force is the opposite that of the direction of our velocities since we assumed them to be positive.
Also this is the force on the ball, the force on the window will be equal and opposite.
Answer:
Trevor's taxi would cause higher levels of air pollution
Explanation:
Trevor's taxi use diesel oil.
Diesel is less cleaner than LPG.
Compared to automotive pollution from petrol and diesel, pollutants from LPG-driven cars include lower amounts of petroleum hydrocarbons, nitrogen oxides , sulphur oxides, ozone contamination and particulate matter.
Cross the railroad tracks but look both ways before crossing over
