Answer:
The car will travel 30 miles during the 30-minutes period of acceleration.
Explanation:
Given data :
Initial velocity = v₁ = 50 miles/hour
Final velocity = v₂ = 70 miles/hour
Time = t = 30 min = 0.5 hour
Using the definition of acceleration, we find the acceleration (a)
a = (v₂ - v₁) ÷ t
a = (70 - 50) ÷ 0.5
a = 20 ÷ 0.5
a = 40 miles/hour²
Using 3rd equation of motion, we find the distance travel (s)
2as = v₂² - v₁²
2(40)s = 70² - 50²
80 × s = 4900 - 2500
s = 2400 ÷ 80
s = 30 miles
Answer:
The spring constant is 3750 N/m
Explanation:
Use the following two relationships:
(Work) = (Force) x (Displacement)
(Force) = (Spring constant) x (Displacement)
=>
(Spring constant) = (Force) / (Displacement) = (Work) / (Displacement)^2
(Spring constant) = 6.0 kg.(m^2/s^2) / 0.0016 m^2 = 3750 N/m
The spring constant is 3750 N/m
All of Dina's potential energy Ep is converted into kinetic energy Ek so Ep=Ek, where Ep=m*g*h and Ek=(1/2)*m*v². m is the mass of Dina, h is the height of ski slope, g=9.8 m/s² and v is the maximal velocity.
So we solve for v:
m*g*h=(1/2)*m*v², masses cancel out,
g*h=(1/2)*v², we multiply by 2,
2*g*h=v² and take the square root to get v
√(2*g*h)=v, we plug in the numbers and get:
v=9.9 m/s.
So Dina's maximum velocity on the bottom of the ski slope is v=9.9 m/s.
I have two (2) brilliant ideas:
1). Inside the metal that the body of the car is made of, and also between the two sheets of glass that the windows are made of, install a thin layer of material that absorbs RF (radio-wave) energy . . . like the material in the glass window of your microwave oven. Then, no radio waves from the cellular base station can get INTO the car, and no radio waves from your phone can get OUT of the car. The phone can't make a connection to the cellular network, you can't make or receive calls, and you can't connect to Instagram or Brainly, so you might as well just turn it off and save your battery until next time you're outside your car.
2). Somewhere inside the car, like under the dash or in the glove box, install a teeny tiny radio receiver that can recognize the signals coming OUT of your phone. Connect it to the car's electrical system so that when it hears signals from phones inside the car, it it shuts down the car's motor so you can't start or drive. The car only works when phones inside the car are either turned off or in Airplane Mode.
My ideas are so brilliant that I really should patent them, or copyright them, or whatever you do so that other people have to pay you to use your idea. But if you want to use them, that's OK. Just go ahead. I won't mind.
