Answer:
1) 460.5 N
2) 431.7 N
Explanation:
Draw a free body diagram. There are four forces on the hammer:
Applied force 62.5 N in the +x direction, 30 cm from the ground
Reaction force Rᵧ in the +y direction, at the point of contact
Reaction force Rₓ in the +x direction, at the point of contact
Reaction force F at 31° from the vertical, 4.75 cm to the left of the point of contact
Part One
To find F, sum the moments about the point of contact:
∑τ = Iα
(62.5 N) (30 cm) − (F cos 31°) (4.75 cm) = 0
F = 460.5 N
Part Two
To find Rₓ and Rᵧ, sum the forces in the x and y directions.
∑Fₓ = ma
62.5 N − F sin 31° + Rₓ = 0
Rₓ = 174.7 N
∑Fᵧ = ma
-F cos 31° + Rᵧ = 0
Rᵧ = 394.7 N
The net reaction force at the point of contact is:
R = √(Rₓ² + Rᵧ²)
R = 431.7 N
Answer with Explanation:
Newton's laws are applicable for inertial frames of reference which is a frame which is not accelerating when seen from the observer standing on earth.
For the person as he presses the brakes his frame is a decelerating frame of reference hence he cannot apply the newtons laws of motion as they are in their original form but if he analyses the motion he has to apply a correction known as pseudo-force on the object he is analyzing. Pseudo Force has no basis in newton's laws but are a correction that needs to be applied if he wishes to analyse the motion from non inertial frame of reference
While as a person standing on earth outside the car since his frame is an inertial frame of reference he can apply newton's laws of motion without any correction.
The echo is weaker than the original sound since the echo has a smaller amplitude than the original sound because sound spreads and its intensity decreases with distance. For example, when the sound from a speaker is heard and is compared to its echo, the echo heard has a lower amplitude than the actual sound.
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