<span>Cobalt-60 is undergoing a radioactivity decay.
The formula of the decay is n=N(1/2)</span>∧(T/t).
<span>Where N </span>⇒ original mass of cobalt
<span> n </span>⇒ remaining mass of cobalt after 3 years
T ⇒ decaying period
t ⇒ half-life of cobalt.
So,
0.675 = 1 × 0.5∧(3/t)
log 0.675 = log 0.5∧(3/t)
3/t = log 0.675 ÷log 0.5
3/t= 0.567
t = 3÷0.567
= 5.290626524
the half-life of Cobalt-60 is 5.29 years.
<span>
</span><span>
</span>
An important difference between a universal and a split-phase motor is that the split-phase motor has
A. two brushes attached to the stator.
B. a single coil formed on the rotor.
<u>C. two windings on the stator. </u>
D. an armature with a commutator.
Explanation:
velocity: average velocity equals Displacement /change in time.
Kinetic energy: K=1/2mv^2 (m = Mass) ( v = Velocity).
speed using the kinetic energy is also KE =1/2mv^2
(M in Kg) (V in m/s)
Answer:
Explanation:
Initial velocity is 0. In the equation v = v0+at where v0 is the initial velocity of 0, we only have to fill in -9.8 for a and 2 for t to get the velocity after 2 seconds -19.6 m/s; after 5 seconds, when it hits the ground, a = -9.8 and t = 5 to give a velocity of -49 m/s. Gravity pulls down everything at the same rate, it doesn't matter whether we drop a feather or an elephant from the window!
