Answer:
0.0000076 grams
Explanation:
We're given the half life of Tritium to be 12.3 years. In order to find out the amount of substabce remaining:
Let's first find how many 'half lives' are in 250 years.
Now what is half life? It means the time taken for a given quantity of an element to lose half it's mass.
So in 12.3 years we can find that The amount of 250 g of Tritium will be 250/2 = 125 g. In 24.6 years we'll have 125/2 = 62.5 g
So now we can devise a formula:
Where m is the remaining amount and n is th number of half lives in the time given.
Using this formula we can calculate:
Doing this calculation we get:
As we can see a very small value remains.
Answer:
Speedometer, instrument that indicates the speed of a vehicle, usually combined with a device known as an odometer that records the distance traveled.
Explanation:
Acceleration is the rate at which velocity changes.
<span>
Simply equate the two.
</span>
<span>dV / dt = F/m </span>
<span>F*dt = dV * m </span>
<span>
The impulse you give any object (average force * time elapsed) is equal to its change in momentum (mass * change in velocity).</span>
The force of friction is <u>34.3 N.</u>
A block of mass m slides down a plane inclined at an angle θ to the horizontal with a constant velocity. According to Newton's first law of motion, every body continues in its state of rest or a state of uniform motion in a straight line, unless acted upon, by an external unbalanced force. This means that when balanced forces act on a body, the body moves with a constant velocity.
The free body diagram of the sliding block is shown in the attached diagram. Resolve the weight mg of the block into two components mg sinθ along the direction of the plane and mg cosθ perpendicular to the plane . The force of friction F acts upwards along the plane and the normal reaction acts perpendicular to the plane.
Since the block moves down with a constant velocity, the downward force mg sinθ must be equal to the upward frictional force.
Substitute 7 kg for m, 9.8 m/s² for g and 30° for θ.
The force of friction is <u>34.3 N</u> up the plane.
1 is A
2 is D
3 is D
4 is B
