Hello!
A 10-kg cart moving at 5 m/s collides with a 5-kg cart at rest and causes it to move 10 m/s. Which principle explains the result? A) law of differential mass B) law of conservation of momentum C) law of unequal forces D) law of accelerated collision
We have the following data¹:
ΔP (momentum before impact) = ?
mA (mass) = 10 kg
vA (velocity) = 5 m/s
mB (mass) = 5 kg
vB (velocity) = 0 m/s
Solving:
ΔP = mA*vA + mB*vB
ΔP = 10 kg*5 m/s + 5 kg*0 m/s
ΔP = 50 kg*m/s + 0 kg*m/s
Δp = 50 kg*m/s ← (momentum before impact)
We have the following data²:
ΔP (momentum after impact) = ?
mA (mass) = 10 kg
vA (velocity) = 0 m/s
mB (mass) = 5 kg
vB (velocity) = 10 m/s
Solving:
Δp = mA*vA + mB*vB
Δp = 10 kg*0 m/s + 5 kg*10 m/s
Δp = 0 kg*m/s + 50 kg*m/s
Δp = 50 kg*m/s ← (momentum after impact)
*** Then, which principle explains the result ?
Law of conservation of momentum, <u>since the total momentum of body A and B before impact is equal to the total momentum of body A and B after impact.</u>
Note: Bodies of different masses and velocities may have the same kinetic energy, if proportionality between the units is maintained it can occur that they have the same kinetic energy.
Answer:
B) law of conservation of momentum
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Answer:
The average induced emf around the border of the circular region is .
Explanation:
Given that,
Radius of circular region, r = 1.5 mm
Initial magnetic field, B = 0
Final magnetic field, B' = 1.5 T
The magnetic field is pointing upward when viewed from above, perpendicular to the circular plane in a time of 125 ms. We need to find the average induced emf around the border of the circular region. It is given by the rate of change of magnetic flux as :
So, the average induced emf around the border of the circular region is .