Answer:
Machine Efficiency
Explanation:
Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work). The output work is always less than the input work because some of the input work is used to overcome friction. Therefore, efficiency is always less than 100 percent
Answer:
Explanation:
Kinetic energy of ball in motion = 1/2 m v² . Potential energy = 0
Let the minimum distance between the balls be d on collision.
Electric potential energy at that time= k Q²/d , Here kinetic energy is converted into potential energy . So
1/2 m v² = kQ²/d
d =2 k Q² / mv²,= 18 x 10⁹ x Q²/ m v².
Answer:
P=2736 Pa
Explanation:
According to Newton we have that:
∑
A force is exerted by the elevator to the suitcase, according to 3th Newton's law an equal force but in the opposite direction will appeared on the suitcase, that is:
∑

We know that the pressure is given by:
Answer:
1210 ohm
Explanation:
Given :
P=40 W
V=220 V
Now,

Therefore, resistance of bulb will be 1210 ohm
Answer:
<em>The total time is: t=451.22 sec</em>
<em>The average speed is: V=34.57 m/s</em>
Explanation:
<u>Average speed</u>
The average speed is calculated by dividing the total distance traveled by an object (x) by the total time it took it to travel that distance (t).

Since the student makes the trip in two parts, we have to calculate the total distance and the total time.
We know the distance to school is 7.8 Km = 7,800 m. The student makes his way home over the same distance, thus the total distance is
x=2*7,800 m=15,600 m
The first trip to school was done at an average speed of v1=32.6 m/s. Knowing the distance and speed, we can calculate the time:

The second trip back home was done at an average speed of v2=36.8 m/s. Let's calculate the second time:

The total time is:


The average speed is:

