Answer:
94 kg
Explanation:
The mass registered by the scale is based on the assumption that the force applied is due entirely to gravity. If the force is greater, then the indicated mass will be greater.
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<h3>how many g's</h3>
As a fraction of the acceleration of gravity, the elevator's acceleration is ...
(1.2 m/s²)/(9.8 m/s²) ≈ 6/49
<h3>net force</h3>
The force required to produce a given acceleration is found by the formula ...
F = ma . . . . . . . force on mass m to produce acceleration 'a'
When the man is stationary on the scale, the upward force it supplies is balanced by the downward force on the man due to gravity. The force and the mass are proportional, and the constant of proportionality (the acceleration due to gravity) is used to calibrate the scale. More force is thus translated to a higher mass reading.
Since the man's net acceleration is upward at the rate of 6/49×g, the total force applied by the scale is (1 +6/49) = 55/49 times as great as when the man is stationary. This greater force gets translated to a greater mass reading.
The force is equivalent to what would be required to support a stationary man with a mass of ...
(84 kg)(55/49) = 94 2/7 kg
The scale would read about 94 kg during the upward acceleration period.
Answer:
* roller skates and ice skates.
* roller coaster
Explanation:
One of the best examples for this situation is when we are skating, in the initial part we must create work with a force, it compensates to move, after this the external force stops working and we continue movements with kinetic energy, if there are some ramps, we can going up, where the kinetic energy is transformed into potential energy and when going down again it is transformed into kinetic energy. This is true for both roller skates and ice skates.
Another example is the roller coaster, in this case the motor creates work to increase the energy of the car by raising it, when it reaches the top the motor is disconnected, and all the movement is carried out with changes in kinetic and potential energy. In the upper part the energy is almost all potential, it only has the kinetic energy necessary to continue the movement and in the lower part it is all kinetic; At the end of the tour, the brakes are applied that bring about the non-conservative forces that decrease the mechanical energy, transforming it into heat.
The vehicle accelerates at 2.648 m/s².
We have:
Initial velocity, u = 50 miles per hour = 22.352 m/s
final velocity, v = 80 miles per hour = 35.762 m/s
Time, t = 5 seconds
The time in hours is:
t = 5 seconds
Now, the acceleration of the car can be calculated using the formula:
v = u + at
35.762 = 22.352 + a(5)
a(5) = 30
a = 2.682 m/s²
From the calculations above, the acceleration of the car is 2.682 m/s².
Ler more about acceleration here:
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Answer:
807.88N/m
Explanation:
<em>The question has some missing details in it, nevertheless, based on the given data we want to find the spring constant K</em>
Step one
given data
Unstretched length = 33.5 cm
Final length of the spring = 42.0 cm
Δx= 42-33.5
Δx=8.5cm to m= 0.085m
mass m= 7kg
The force on the spring
F=mg
F= 7*9.81
F=68.67N
Step two:
From Hooke's law, we can make k subject of formula and find the spring constant k, we have
F=kΔx---------1
make k subject of the formula
k=F/Δx
k= 68.67/ 0.085
k=807.88N/m
Answer:
Explanation:
Young's modulus of elasticity Y = stress / strain
stress = force / cross sectional area
= weight of 15 kg / π r²
= 15 x 9.8 / 3.14 x ( .025 x 10⁻² )²
stress = 74.9 x 10⁷ N / m²
strain = Δ L / L , Δ L is change in length and L is original length
Putting the values
strain = .0168 / 2.7 =.006222
Young's modulus of elasticity Y = 74.9 x 10⁷ / .006222
= 120.88 x 10⁹ N / m² .