Explanation:
a) d = ½.a.t²
200 = ½(4)t²
200 = 2t²
t² = 200/2
t² = 100
t =√100 = 10 s
b) Vt = a. t
= 4(10)
= 40 m/s
c) V av. = d/t = 200/10 = 20m/s
Answer:
A half-life is the time required for one half of the nuclei in a radio- active isotope to decay.
Explanation:
A radio-active isotope is an isotope which undergoes radioactive decay.
Radioactive decay is a spontaneous process in which the nucleus of an atom changes its state (turning into a different nucleus, or de-exciting), emitting radiation, which can be of three different types: alpha, beta or gamma.
The half-life of a radio-active isotope is the time required for half of the nuclei of the initial sample to decay.
The law of radio-active decay can be expressed as follows:
where
N(t) is the number of undecayed nuclei left at time t
N0 is the initial number of nuclei
t is the time
is the half-life
We see that when 
(that means, when 1 half-life has passed), the number of undecayed nuclei left is
So, half of the initial nuclei.
Answer:
111.5 m
Explanation:
Given that You are driving to the grocery store at 14 m/s. You are 115 m from an intersection when the traffic light turns red. Assume that your reaction time is 0.50 s and that your car brakes with constant acceleration.
Use first equation of motion
V = U - at
Since the car is going to rest, V = 0 and a = negative
0 = 14 - a × 0.5
0.5a = 14
a = 14 /0.5
a = 28 m/s^2
Let us use second equation of motion
S = Ut - 1/2at^2
S = 14 × 0.5 - 0.5 × 28 × 0.5^2
S = 7 - 3.5
S = 3.5 m
115 - 3.5 = 111.5
Therefore, you are 111.5 metres from the intersection (in m) when you begin to apply the brakes.
Answer:
0
Explanation:
It’s before the projectile was fired, so nothing has happened yet.
Total amount of energy would remain constant according to law of conservation of energy. i.e., 50 Joules
In short, Your Answer would be Option C) <span>50 Joules because as energy converts from one form to another, it cannot be created or destroyed during the conversion.
</span>
Hope this helps!
