A car travels 40 miles in 30 min. Calculate the car's average speed in mi/hr.
2 answers:
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Answer:
D) The worker will accelerate at 2.17 m/s² and the box will accelerate at 1.08 m/s² , but in opposite directions.
Explanation:
Newton's third law
Newton's third law or principle of action and reaction states that when two interaction bodies appear equal forces and opposite directions. in each of them.
F₁₂= -F₂₁
F₁₂: Force of the box on the worker
F₂₁: Force of the worker on the box
Newton's second law
∑F = m*a
∑F : algebraic sum of the forces in Newton (N)
m : mass in kilograms (kg)
a : acceleration in meters over second square (m/s²)
Formula to calculate the mass (m)
m = W/g
Where:
W : Weight (N)
g : acceleration due to gravity (m/s²)
Data
W₁ =1.8 kN : box weight
W₂ = 0.900 kN : worker weight
F₂₁ = 0.200 kN
F₁₂ = - 0.200 kN
g = 9.8 m/s²
Newton's second law for the box
∑F = m*a
F₂₁ = m₁*a₁ m₁=W₁/g
0.2 kN = (1.8kN)/(9.8 m/s² ) *a₁
a₁= 1.08 m/s² : acceleration of the box
Newton's second law for the worker
∑F = m*a
F₁₂ = m₂*a₂ , m₂=W₂/g
- 0.2 kN =( (0.9 kN) /(9.8 m/s² ) )*a₂
a₂= -2.17 m/s² : acceleration of the worker