Answer:
Explanation:
Given
Each student exert a force of
Let mass of car be m
there are 18 students who lifts the car
Total force by 18 students
therefore weight of car
mass of car
(b)
Answer: The copper wiring most likely caused the mini-refrigerator fire.
Explanation: A mini-refrigerator may have one or more evaporator fan motors. These motors have copper wiring. In some situation these copper wires gets overheated. It may result to the firing of the mini-refrigerator.
Therefore, the mini-refrigerator fire was most likely caused by copper wiring.
Answer:
v = 10 m/s
Explanation:
Let's assume the wheel does not slip as it accelerates.
Energy theory is more straightforward than kinematics in my opinion.
Work done on the wheel
W = Fd = 45(12) = 540 J
Some is converted to potential energy
PE = mgh = 4(9.8)12sin30 = 235.2 J
As there is no friction mentioned, the remainder is kinetic energy
KE = 540 - 235.2 = 304.8 J
KE = ½mv² + ½Iω²
ω = v/R
KE = ½mv² + ½I(v/R)² = ½(m + I/R²)v²
v = √(2KE / (m + I/R²))
v = √(2(304.8) / (4 + 0.5/0.5²)) = √101.6
v = 10.07968...
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I'm not really sure but I do know that it's not 0 because the object is still moving, even if it's only moving at 1 m/s.
Answer:
a) 35.44 mm
b) 17.67 mm
Explanation:
u = Object distance = 3.6 m
v = Image distance
f = Focal length = 35 mm
= Object height = 1.8 m
a) Lens Equation
The CCD sensor is 35.34 mm from the lens
b) Magnification
The person appears 17.67 mm tall on the sensor