As per FBD while its accelerating upwards
we can say that

here normal force is given as


now mass is given as


now we will have


Now while accelerating downwards we can say by FBD

again plug in all values


Answer: an element; a compound
A compound is a molecule with at least two kinds of atoms. Since iron is only containing Fe then it shouldn't be a compound.
After iron got rust reaction, it will have oxygen make it become iron oxide. The iron oxide having Fe and O so it is a compound.
Answer:
Explanation:
Let T be the tension
For linear motion of hoop downwards
mg -T = ma , m is mass of the hoop . a is linear acceleration of CG of hoop .
For rotational motion of hoop
Torque by tension
T x R , R is radius of hoop.
Angular acceleration be α,
Linear acceleration a = α R
So TR = I α
= I a / R
a = TR² / I
Putting this value in earlier relation
mg -T = m TR² / I
mg = T ( 1 + m R² / I )
T = mg / ( 1 + m R² / I )
mg / ( 1 + R² / k² )
Tension is less than mg or weight because denominator of the expression is more than 1.
<span>15 m/s^2
The first thing to calculate is the difference between the final and initial velocities. So
180 m/s - 120 m/s = 60 m/s
So the plane changed velocity by a total of 60 m/s. Now divide that change in velocity by the amount of time taken to cause that change in velocity, giving
60 m/s / 4.0 s = 15.0 m/s^2
Since you only have 2 significaant figures, round the result to 2 significant figures giving 15 m/s^2</span>
Answer:
4400 N
Explanation: (c)
P= 
F= PA
P= pressure
A= area
P=800x
and A= 5.5 x 

Force F= 800x
x0.0055= 4400 N
force exerted by the gas on the piston is 4400 N