After working in a fast-food restaurant for three years to pay for your college tuition, you vowed never to work in a restaurant
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The acceleration of the object if the net force is decreased = 0.13 m/s²
<h3>Further explanation</h3>Given
A net force of 0.8 N acting on a 1.5-kg mass.
The net force is decreased to 0.2 N
Required
The acceleration of the object if the net force is decreased
Solution
Newton's 2nd law :
The mass used in state 1 and 2 remains the same, at 1.5 kg
- state 1
ΣF=0.8 N
m=1.5 kg
The acceleration, a:
- state 2
ΣF=0.2 N
m=1.5 kg
The acceleration, a:
Answer:
a) It is moving at when reaches the ground.
b) It is moving at when reaches the ground.
Explanation:
Work energy theorem states that the total work on a body is equal its change in kinetic energy, this is:
(1)
with W the total work, Ki the initial kinetic energy and Kf the final kinetic energy. Kinetic energy is defined as:
(2)
with m the mass and v the velocity.
Using (2) on (1):
(3)
In both cases the total work while the objects are in the air is the work gravity field does on them. Work is force times the displacement, so in our case is weight (w=mg) of the object times displacement (d):
(4)
Using (4) on (3):
(5)
That's the equation we're going to use on a) and b).
a) Because the branch started form rest initial velocity (vi) is equal zero, using this and solving (5) for final velocity:
b) In this case the final velocity of the boulder is instantly zero when it reaches its maximum height, another important thing to note is that in this case work is negative because weight is opposing boulder movement, so we should use -mgd:
Solving for initial velocity (when the boulder left the volcano):