(a) The skater covers a distance of S=50 m in a time of t=12.1 s, so its average speed is the ratio between the distance covered and the time taken:

(b) The initial speed of the skater is

while the final speed is

and the time taken to accelerate to this velocity is t=2 s, so the acceleration of the skater is given by

(c) The initial speed of the skater is

while the final speed is

since she comes to a stop. The distance covered is S=8 m, so we can use the following relationship to find the acceleration of the skater:

from which we find

where the negative sign means it is a deceleration.
Answer:
6 A
Explanation:
First of all, we need to calculate the equivalent resistance of the circuit. The three resistors are connected in parallel, so their equivalent resistance is given by:

And now we can use Ohm's law to find the current in the circuit:

Answer:
This is how I figured it out:
- 215.5 rounded to one significant figure is 200
- 101.02555 rounded to one significant figure is 100.
- 200 + 100 = 300.
Hope this helps!
Explanation:
Answer:
A) Out of the page.
Explanation:
Right-hand rule points the direction of the magnetic field at any point.
<u>Top wire</u>: Current is to the left. Point your thumb to the left and curl your other fingers around the wire. The tips of the four fingers points the direction of the field at that point. In this case, out of the page.
<u>Bottom wire</u>: Current is to the right. Point your thumb to the right and curl your other fingers around the wire. The tips of the four finger points out of the page again.
So, the total field produced by both wires is directed out of the page.
Another method to figure out the direction is the mathematical method.
Use the B-field formula:

The cross product between the direction of the current and the target position gives the direction of the B-field. If the left is -x direction and downwards is the -y direction, then
for the top wire.
for the bottom wire.