Answer:
Yep! it's correct might need to double check tho
If it starts from twice the height, then it has twice the potential energy up there. This means it'll have twice the kinetic energy when it hits the ground.
Hi there!
To find the appropriate force needed to keep the block moving at a constant speed, we must use the dynamic friction force since the block would be in motion.
Recall:

The normal force of an object on an inclined plane is equivalent to the vertical component of its weight vector. However, the horizontal force applied contains a vertical component that contributes to this normal force.

We can plug in the known values to solve for one part of the normal force:
N = (1)(9.8)(cos30) + F(.5) = 8.49 + .5F
Now, we can plug this into the equation for the dynamic friction force:
Fd= (0.2)(8.49 + .5F) = 1.697 N + .1F
For a block to move with constant speed, the summation of forces must be equivalent to 0 N.
If a HORIZONTAL force is applied to the block, its horizontal component must be EQUIVALENT to the friction force. (∑F = 0 N). Thus:
Fcosθ = 1.697 + .1F
Solve for F:
Fcos(30) - .1F = 1.697
F(cos(30) - .1) = 1.697
F = 2.216 N
Answer:
0.42 meters/second
Explanation:
The total distance traveled by Mary is: 80 m + 125 m + 45 m = 250 m
We want the speed in meters/second, so we have to convert the 10 minutes elapsed during the trip into seconds. Then we need a conversion factor, 1 minute is equivalent to 60 seconds.
time = 10 minutes * (60 seconds/1 minute) = 600 seconds (notice that minute is cancelled because is multiplying and dividing)
Now, we can compute the average speed is as follows:
Average speed = total distance/time = 250 m/600 s = 0.42 m/s
Answer: The first one
Explanation:
Because it’s the higher frequency