Answer:
a) 
Now we can replace the velocity for t=1.75 s

For t = 3.0 s we have:

b) 
And we can find the positions for the two times required like this:
And now we can replace and we got:

Explanation:
The particle position is given by:

Part a
In order to find the velocity we need to take the first derivate for the position function like this:

Now we can replace the velocity for t=1.75 s

For t = 3.0 s we have:

Part b
For this case we can find the average velocity with the following formula:

And we can find the positions for the two times required like this:
And now we can replace and we got:

T = ?
v1 = 0mph
v2 = 60mph
a = 8.7mph/s

Therefore, it takes 6.90 seconds for Jill to accelerate from 0 to 60 miles per hour.
Answer:
550000000N/m
Explanation:
Given that a copper wire has a radius of 2.9 mm. When forces of a certain equal magnitude but opposite directions are applied to the ends of the wire, the wire stretches by 5.0×10−3 of its original length.
Original length L = 0.005L
the strain = extension/ original length
the strain = 0.005L / L
the strain = 0.005
Young modulus = stress / strain
11 × 10^10 = stress / 0.005
Cross multiply
Stress = 11 × 10^10 × 0.005
Stress = 550 000000 N/m
Therefore, the tensile stress on the wire is 550000000 N/m.
Turning on a flashlight uses a battery, right? Chemical energy is stored in that battery. If you use the battery, you're converting that chemical energy to an electrical energy.
In a flashlight then, the electrical energy becomes light energy and thermal energy in the bulb. Why light and thermal? The flashlight gives us light and then, gives out heat. This is why when we touch light bulbs, it feels hot.
I hope you find this answer the most helpful! :)
False. Both masses will experience an acceleration which depends on their mass. The small mass will experience a greater acceleration.