Electric motors require electricity to move the motor parts and do work (like an electric fan).
Elecgric generators actually burn diesel fuel to spin a motor around and around and around to GENERATE, or MAKE, electricity that you can then use to power your fans and lights in your house.
When a force pushes or pulls the object, the object will move in the direction of the force. Force can make things move, change shape or change their speed. Some forces are direct and happen when two things touch (like a foot kicking a ball) or over a distance (such as a magnet or gravity)
Answer:
so initial speed of the rock is 30.32 m/s
correct answer is b. 30.3 m/s
Explanation:
given data
h = 15.0m
v = 25m/s
weight of the rock m = 3.00N
solution
we use here work-energy theorem that is express as here
work = change in the kinetic energy ..............................1
so it can be written as
work = force × distance ...................2
and
KE is express as
K.E = 0.5 × m × v²
and it can be written as
F × d = 0.5 × m × (vf)² - (vi)² ......................3
here
m is mass and vi and vf is initial and final velocity
F = mg = m (-9.8) , d = 15 m and v{f} = 25 m/s
so put value in equation 3 we get
m (-9.8) × 15 = 0.5 × m × (25)² - (vi)²
solve it we get
(vi)² = 919
vi = 30.32 m/s
so initial speed of the rock is 30.32 m/s
Answer:
Ali hear the sound in 0.046 seconds.
Explanation:
Given:
Distance between Ali and Abdi = 300m
Speed of sound in steel = 6500m/s
To Find :
How much sooner does Ali hear the sound = ?
Solution:
We can find the time in which the sound made by Abdi with a stone on the rail by using the speed formula
We know that
On substituting the given values,
Time = 0.046 seconds