Answer:
The law of refraction states that the incident ray, the refracted ray, and the normal to the interface, all lie in the same plane.
Explanation:
The atomic number tells you the number of protons in an atom. This value never changes because the number of protons in the nucleus always remains constant. The mass number tells you the number of protons and neutrons (or nucleons) together: protons + neutrons = mass number. Since the number of neutrons in the nucleus varies, you can have different amounts of neutrons in the same type of atom. These varied types are called isotopes.
Hope this helps.
Angular velocity = (75x2pie)/60
=2.5pie ras^-1
linear velocity(or speed) at end of string, v = radius x angular velocity
v= 0.5 x 2.5pie
v=3.93 ms^-1
tension of string (I beleve is centeral force aplied by string), F= (mv^2)/r
F= (0.2 x 3.93^2)/0.5
F=6.18 N
(sorry if wrong)
Answer:
159.38 Watts
Explanation:
Initially;
- Mass on the spring is 8.5 kg
- Therefore, compression force is 85 N
- Compression distance is 15 cm or 0.15 m
But;
F = kx
where F is the force of compression, k is the spring constant and x is the compression distance.
Thus;
k = F/x
= 85 N ÷0.15
= 566.67 N/m
We are required to determine the power needed to stretch the same spring for 1.5 m in 4 secs.
Power = Work done ÷ time
Work done is given by 0.5kx²
Therefore;
Power = 0.5kx²÷ t
= (0.5×566.67 N/m × 1.5² ) ÷ 4 seconds
= 159.38 Watts
Thus, the power needed is 159.38 watts
Well, they're not quite the way Newton expressed it, but out of all this mess of statements, there are two that are correct AND come from Newton's 2nd Law of Motion:
<em>-- The smaller the mass of an object, the greater the acceleration of that object when a force is applied. </em>
<em>-- The greater the force applied, the greater the acceleration.</em>
For the <u><em>other </em></u>statements in the question:
-- <em>Every reaction is equal to the force applied.</em> True; comes from Newton's <u><em>3rd</em></u> law of motion.
-- <em>Forces are balanced when they are equal and opposite.</em> True; kind of a definition, not from Newton's laws of motion.
-- <em>An object at rest or in motion will remain at rest or in motion unless acted upon by an unbalanced force.
</em> True; comes from Newton's <em><u>1st </u></em>law of motion.