Answer: 96N
Explanation:
To calculate the velocity of the impact On the persons head, we have
h = gt²/2
14 = 9.81t²/2
t² = 28/9.8
t² = 2.86
t = 1.69s
V = u + at
V = 0 + 9.81*1.69
V = 16.58m/s
a(average) = (v1² + v2²) /2Δy
a(average) = 16.58² + 0)/2 * 0.005
a(average) = 274.8964/0.01
a(average) = 27489.64m/s²
Using newton's second law of motion,
F(average) = m * a(average)
F(average) = 0.0035 * 27489.64
F(average) = 96.21N
Therefore the force needed by the acorn to do much damage starts from 96N
We have 2 conditions of balance. First of all, the total forces have to have a net sum of 0 since the bridge is balancing. Hence, if we denote by F1 the force of the first pole, F2 the power of the second pole (the one closer to the car), W the weight of the bridge and w the weight of the car, we have that W+w=F1+F2=4.196*10^5 N.
We also have that it does not rotate. Hence, taking as origin of our frame of reference the car, we have that 5*F2+4*W=9*F2 by calculating the distances from our point of reference. Thus yields 5F2+8*10^5=9F2. When we solve the system of equations that is created above (best way here is by substitution), we get that F1=2.07*10^5 N while F2=2.126*10^5 N . Each pole takes up around half the weight but due to the car the pole closer to it has more weight to bear; nevertheless the car does not weigh a lot so the difference is small.
What you see rising from the road ... and call "heat waves" ...
are rising currents of air. The air that's been heated by
contact with the hot asphalt rises. (Why ? By being heated,
it becomes less dense than the other air around it, and the
buoyant force of being a less dense substance in a more dense
fluid makes it rise (float) ).
If we want to paint a complete picture, we can find all three
types of heat transfer going on here:
1). The air getting heated by direct contact with the hot road ==> conduction
2). The hot air rising through the cooler air around it ==> convection
3). How the road got so hot in the first place ==> radiation, from the sun
Answer:
C. has no effect on validity
Explanation:
Repeating your experiment has no effect on validity.
It doesn't matter how many times you repeat your experiment. You have to find the average outcome of each experiment you do.
It’s either Asia or the America
