The height of the ball above the ground is 38.45 m
First we will calculate the velocity of the ball when it touch the ground by using first equation of motion
v=u+gt
v=0+9.81×2.8
v=27.468 m/s
now the height of the ground can be calculated by the formula
v=√2gh
27.468=√2×9.81×h
h=38.45 m
The force ratio of a machine is 4 and it velocity ratio is 4 means that the load moved is four times the effort applied and the distance moved by the effort is five times the distance moved by the load at the same time interval.
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Speed is the rate of distance traveled per unit of time without regards to direction.
<u>Explanation</u>:
Speed is the pace of separation traveled per unit of time, regardless of direction.
Speed is straightforwardly relative to separate when time is consistent and conversely corresponding to a time when separation is steady. Multiplying one's speed would mean multiplying one's separation went in a given measure of time. Multiplying one's speed would likewise mean splitting the time required to travel a given separation.
All these resistors are in series so we can take the sum of them by:
Rtotal = R1 + R2 + R3......
So...
Rtotal = 2 + 3 + 4 + 6
Rtotal = 15
So now the total resistance in the circuit is 15 ohms and the potential difference applied to the circuit is 45 volts
Now we can use:
V = IR
Isolate for I
V/R = I
45/15 = I
I = 3 amps (A)
Answer:
because our some of the energy goes from our eyes
explanation;
There are several reasons why it's important to close our eyes while we sleep. Closed eyelids block light, which stimulates the brain to wakefulness. Closing our eyes also protects and lubricates the eyes while we sleep