We are usually not aware of the electric force acting between two everyday objects because
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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 answer to the question is
The roller coaster will reach point B with a speed of 14.72 m/s
Explanation:
Considering both kinetic energy KE = 1/2×m×v² and potential energy PE = m×g×h
Where m = mass
g = acceleration due to gravity = 9.81 m/s²
h = starting height of the roller coaster
we have the given variables
h₁ = 36 m,
h₂ = 13 m,
h₃ = 30 m
v₁ = 1.00 m/s
Total energy at point 1 = 0.5·m·v₁² + m·g·h₁
= 0.5 m×1² + m×9.81×36
=353.66·m
Total energy at point 2 = 0.5·m·v₂² + m·g·h₂
= 0.5×m×v₂² + 9.81 × 13 × m = 0.5·m·v₂² + 127.53·m
The total energy at 1 and 2 are not equal due to the frictional force which must be considered
Total energy at point 2 = Total energy at point 1 + work done against friction
Friction work = F×d×cosθ = ( × mg)×60×cos 180 = -117.72m
0.5·m·v₂² + 127.53·m = 353.66·m -117.72m
0.5·m·v₂² = 108.41×m
v₂² = 216.82
v₂ = 14.72 m/s
The roller coaster will reach point B with a speed of 14.72 m/s