Question: Find acceleration of a refrigerator 30s after a person begins pushing it at a force of 400 N, If the mass of the refrigerator is 10 kg.
Answer:
40 m/s²
Explanation:
Applying,
F = ma................Equation 1
Where F = Force applied to the refrigerator, m = mass of the refrigerator, a = acceleration of the refrigerator.
make a the subject of the equation
a = F/m............ Equation 2
From the question,
Given: F = 400 N, m = 10 kg
Substitute these values into equation 2
a = 400/10
a = 40 m/s²
The easiest, non-technical way to think about it is like this:
-- A scalar is a quantity that has a size but no direction.
Those include temperature, speed, cost, volume, distance, etc.
One number is all there is to know about it, and there's no way you can
add more of the same stuff to it that would cancel both of them out.
-- A vector is a quantity that has a size and also has a direction.
Those include force, displacement, velocity, acceleration, etc.
It takes more than one number to completely describe one of these.
Also, if you combine two of the same vector quantity in different ways,
you can get different results, and they can even cancel each other out.
Here are some examples. Notice that in each of these examples,
every speed has a direction that goes along with it. This turns the
scalar speed into a vector velocity.
If you're walking inside a bus, and the bus is driving along the road,
then your velocity along the road is the sum of your walking velocity
inside the bus plus the velocity of the bus along the road.
-- If you're walking north up the middle of the bus at 2 miles per hour
and the bus is driving north along the road at 20 miles per hour, then
your velocity along the road is 22 miles per hour north.
-- If you're walking south towards the back of the bus at 2 miles per hour
and the bus is driving north along the road at 5 miles per hour, then your
velocity along the road is 3 miles per hour north.
-- If you're walking south towards the back of the bus at 2 miles per hour
and the bus is just barely rolling north along the road at 2 miles per hour,
then your velocity along the road is zero.
-- If you're in a big railroad flat-car that's rolling north along the track
at 2 miles per hour, and you walk across the flat-car towards the east
at 2 miles per hour, then your velocity along the ground is 2.818 miles
per hour toward the northeast.
Answer:
surface charge density on each sphere is 
C
Explanation:
given data
radius of smaller sphere = 5 cm
radius of larger sphere is 12 cm
electric field at surface of larger sphere = 660 kV/m = 660 × 1000 v/m
solution
we apply here electric field formula that is express as
E = 
.................1
put here value
660000 = 
Q1 = 1056 × 
and
here field inside a conductor is zero so that electric potential ( V ) is constant
..................2
so Q2 will be
Q2 = 
Q2 = C
Answer:
Ball hit the tall building 50 m away below 10.20 m its original level
Explanation:
Horizontal speed = 20 cos40 = 15.32 m/s
Horizontal displacement = 50 m
Horizontal acceleration = 0 m/s²
Substituting in s = ut + 0.5at²
50 = 15.32 t + 0.5 x 0 x t²
t = 3.26 s
Now we need to find how much vertical distance ball travels in 3.26 s.
Initial vertical speed = 20 sin40 = 12.86 m/s
Time = 3.26 s
Vertical acceleration = -9.81 m/s²
Substituting in s = ut + 0.5at²
s = 12.86 x 3.26 + 0.5 x -9.81 x 3.26²
s = -10.20 m
So ball hit the tall building 50 m away below 10.20 m its original level
<span>b. It ensures that measurements are taken from two points
that are very far apart.
Measurements taken six months apart are the farthest apart
that an astronomer can ever get ... they're on opposite sides
of the Earth's orbit !</span>
