Answer:
The time taken to stop the box equals 1.33 seconds.
Explanation:
Since frictional force always acts opposite to the motion of the box we can find the acceleration that the force produces using newton's second law of motion as shown below:

Given mass of box = 5.0 kg
Frictional force = 30 N
thus

Now to find the time that the box requires to stop can be calculated by first equation of kinematics
The box will stop when it's final velocity becomes zero

Here acceleration is taken as negative since it opposes the motion of the box since frictional force always opposes motion.
The glowing beam was repelled by a negatively charged plate because they were negatively charged
<h3>What are the nature of charges?</h3>
The nature of charges refers to the properties of charges.
There are two types of charges:
- negative charges
- positive charges
The law of electricity states that opposite charges attract whereas like charges repel.
Therefor, in Thomson’s experiment, the glowing beam was repelled by a negatively charged plate because they were negatively charged
In conclusion, like charges repel while opposite charges attract.
Learn more about charges at: brainly.com/question/12781208
#SPJ1
Twenty is the atomic number of potassium.
Answer:
moment of inertia is 2.72 kg m²
Explanation:
given data
mass m = 10kg
height h = 4.5 m
radius r = 0.5 m
speed v = 6.5 m/s
to find out
moment of inertia
solution
we apply here conservation of energy
that is
mgh = 1/2 ×mv² + 1/2 × Iω²
here I is moment of inertia we find and
we know ω = Velocity / radius = 6.5 / 0.5 = 13
and g = 9.8
so put here all these value
10 (9.8) 4.5 = 1/2 ×(10)(6.5)² + 1/2 × I(13)²
441 = 211.25 + 1/2 × I( 169 )
I = 2.72
so moment of inertia is 2.72 kg m²
a) 10 m/s
b) 25 m
Explanation:
a)
The body is moving with a constant acceleration, therefore we can solve the problem by using the following suvat equation:

where
u is the initial velocity
v is the final velocity
a is the acceleration
t is the time
For the body in this problem:
u = 0 (the body starts from rest)
is the acceleration
t = 5 s is the time
So, the final velocity is

b)
In this second part, we want to calculate the distance travelled by the body.
We can do it by using another suvat equation:

where
u is the initial velocity
v is the final velocity
a is the acceleration
s is the distance travelled
Here we have
u = 0 (the body starts from rest)
is the acceleration
v = 10 m/s is the final velocity
Solving for s,
