Answer:
95 J
Explanation:
You can calculate efficiency by dividing useful output by total input, then multiplying it to 100.
So the foumula goes like:
Efficiency= (Useful output/Total input)x100
In this question,
Efficiency= 95%
Useful output= x
Total input= 200
Therefore;
95=(x/200)x100
0.95=x/100
x=0.95x100
x=95 Joules
Answer:
120 miles per hour.
Explanation:
We need to find the time it takes my parents to drive home from the cottage. Since my father drives at 60 miles per hour, and the cottage is 240 miles from our home, and distance = speed × time. So, time = distance/speed = 240 mi/60 mi/h = 4 h.
So, it will take my father 4 hours to drive home from the cottage.
Since I have 2 hours to prepare for the party, the time left for me to drive to the cottage is 4 - 2 hrs = 2 hrs.
So, I'm supposed to drive to the cottage in at most 2 hours.
The speed at which I must drive in this time period is thus, speed = distance/time = 240 miles/2 hours = 120 miles per hour.
So, I must drive at a minimum speed of 120 miles per hour.
Answer:
22.17 degree
Explanation:
n = 1.52
Angle of incidence, i = 35 degree
Let the angle of refraction is r.
use the Snell's law
n = Sin i / Sin r
Sin r = Sin i / n = Sin 35 / 1 .52
Sin r = 0.37735
r = 22.17 degree
Thus, the ray is refracted at an angle of 22.17 degree.
