Answer:
<u><em>A for certain.</em></u>
Explanation:
I got it right on the test, thanks to the other brainly answerer teresecaway. But knowing the answer doesnt help much if you dont know WHY. The reason WHY is as follows. At first you might think it would be B, because the downwards force is greater than the upwards force. I thought that maybe upwards force would also count as the table supporting it, but no, thats just structural inanimate solid table. The answer is A. gravity would have to be HIGHLY raised or somebody pressing down on it, to make it fall through the table.
<span>You can use the equation
V_xf = V_xi + a_x(t)
V_xf = 20.0m/s
V_xi = 0m/s
ax = 2.0
t
Thus, solve for t and get 10seconds
and then take 5 seconds to break after 20 seconds of driving
so for
a) 10 + 20 + 5 = 35 seconds
</span><span>for part b)
You can use the formula
Delta x/Delta t = average velocity
Need to find xf, knowing xi = 0
Thus, use the formula
x_f = x_i + V_xi(t) + (1/2)a_x(t)^(2)
x_f = 0 + 0(10) + (1/2)(2.0)(10)^(2)
x_f = 100m
so for the first 10 seconds the truck traveled 100ms
At a speed of 20m/s
20m/s = xm/20s
20*20 = x
x = 400
thus we have 100+400 = 500m
then it slows down from 500m to x_f
thus I use the equation
x_f = x_i + (1/2)(V_xf + V_xi)t
x_f = 500 + (1/2)(0 + 20)(5)
x_f = 500 + 50
x_f = 550
therefore the total distance traveled is 550m
</span>
<span>to calculate average velocity
550/35 = 16m/s
thus
V_xavg = 16m/s</span>
Answer:
At the center of the object
At the end of the object farthest away from the ground
At the center of gravity of the object
At end of the object closest to the ground
Explanation:
The thermal efficiency is defined as follows

,
and the energy which is put into the system is

.
In your case

So

which gives an efficiency of

.
D) Submarine is your answer. Have a great rest of your day!