Answer:
The time take is 
Explanation:
From the question we are told that
The decay constant is
The percentage fall is 
The equation for radioactive decay is mathematically represented as

Where is
is the new amount of the new the isotope while
is the original
At initial
% = 1
At
% = 0.80

=> 
=> 
Answer:
Distance = 64 metres
Displacement = 28 metres
Direction = northward
Explanation:
Given that a kayaker moves 22 meters northward, then 18 meters southward , and finally 24 meters northward
Distance covered is only about the magnitude of the length covered.
Distance = 22 + 18 + 24 = 64 metres
The direction will be considered when calculating the displacement
Let northward be positive and southward be negative
Displacement = 22 - 18 + 24 = 28 metres
Since the displacement is positive, the direction of the motion is northward.
NH4OH is the answer. Hope this helps you.
Answer:
1)The position change of almost any manually operated room light switch.
2) Sunlight striking a point on the ground on a partly cloudy and windy day
Explanation:
Answer:
The mass of the man is 71 kg
Explanation:
Given;
kinetic energy of the man, K.E = 887.5 J
velocity of the man, v = 5 m/s
The mass of the man is calculated as follows;
K.E = ¹/₂mv²
where;
m is the mass of the man
2K.E = mv²
m = 2K.E / v²
m = (2 x 887.5) / (5)²
m = 71 kg
Therefore, the mass of the man is 71 kg