Via half-life equation we have:
Where the initial amount is 50 grams, half-life is 4 minutes, and time elapsed is 12 minutes. By plugging those values in we get:
There is 6.25 grams left of Ra-229 after 12 minutes.
Answer:
d = 10.2 m
Explanation:
When the car travels up the inclined plane, its kinetic energy will be used to do the work in climbing up. So according to the law of conservation of energy, we can write that:
where,
m = mass of car
v = speed of car at the start of plane = (36 km/h)(1000 m/1 km)(1 h/3600 s)
v = 10 m/s
F = force on the car in direction of inclination = W Sin θ
W = weight of car = mg
θ = Angle of inclinition = 30°
d = distance covered up the ramp = ?
Therefore,
<u>d = 10.2 m</u>
Answer:
The pickup truck and hatchback will meet again at 440.896 m
Explanation:
Let us assume that both vehicles are at origin at the start means initial position is zero i.e. = 0. Both the vehicles will cross each other at same time so we will make equations for both and will solve for time.
Truck:
= 33.2 m/s, a = 0 (since the velocity is constant), = 0
Using
s = 33.2t .......... eq (1)
Hatchback:
, = 0 m/s (since initial velocity is zero), = 0
Using
putting in the data we will get
now putting 's' value from eq (1)
which will give,
t = 13.28 s
so both vehicles will meet up gain after 13.28 sec.
putting t = 13.28 in eq (1) will give
s = 440.896 m
So, both vehicles will meet up again at 440.896 m.
Answer:
Magnetic field, B = 0.23 T
Explanation:
Given that,
Length of the copper rod, L = 0.49 m
Mass of the copper rod, m = 0.15 kg
Current in rod, I = 13 A (in +ve y direction)
When the rod is placed in magnetic field, the magnetic force is balanced by its weight such that :
So, the magnitude of the minimum magnetic field needed to levitate the rod is 0.23 T.