Answer:
The magnitude of the force is 64.634 newtons.
Explanation:
According to the statement, the crate is a constant mass system, whose upward force is described by the following expression:
(1)
Where:
- Force, in newtons.
- Mass, in kilograms.
- Acceleration, in meters per square second.
The function acceleration is obtained by deriving the function position twice in time:
(2)
(3)
And we expand (1) by applying (3):
Where is the time, in seconds.
If we know that and , then the magnitude of the force is:
The magnitude of the force is 64.634 newtons.
10 grams of salt is the result
Answer:
Explanation:
<u>1) Data:</u>
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a) m =750 kg
b) V₀ = 0 (at rest at the red light)
c) a = 7.8 m/s²
d) t = 7.0 s
e) Vf (at t = 7 s) = ?
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<u>2) Physical principles and formulae</u>
Uniformly accelerated motion is ruled by the equations:
i. Vf= V₀ + at
ii. d = V₀ t + at² / 2
iii. Vf² = V₀² + 2ad
Where:
- V₀ = initial speed
- Vf = final speed
- a = acceleration
- d = distance run
<u>3) Solution</u>
You just need to use the first equation:
- Vf= V₀ + at = 0 + 7.8 m/s² × 7 s = 74.6 m/s
- Round to two significant figures: 75 m/s