It's been a while since I've studied this, but my answers would be:
13. 5730 years. The half-life of a substance is the amount of time it takes for half of it to decay, and, according to the graph, half of the substance remained at 5730 years.
14. 10740 years. According to the graph, only 25% of the carbon remained after 10740 years.
15. 15 atoms. According to the graph, only 12.5% of the carbon remained after 16110 years. 12.5% of 120 atoms is 15 atoms.
16. 1600 atoms. According to the graph, if a sample of carbon is 10740 years old, only 25% of it remains. To find the original amount, multiply the current amount by (100% / 25%), which equals 4. So, 4. 400 atoms * 4 = 1600 atoms is the original amount.
Answer:
Explanation:
Given
mass of book(m)=2.1 kg
height up to which book is lifted is (h)2.2 m
height of person
Potential energy of book relative to ground=mgh
(b)PE w.r.t to person head =mg(h-h0)
work done by person in lifting box 2.2 m w.r.t floor
Word done =Potential Energy of box relative to floor=45.2 J
Answer:
increased by 9 times
Explanation:
As the period of a simple pendulum is defined as the following formula
where L is the length of the pendulum and g is the constant gravitational acceleration. Since L is under a square root, if you want to triple the period of vibration, L must be increased by 9 times so that
Answer:
<em>a. q=450 c
</em>
<em>b. E=675 J
</em>
Explanation:
<u>Direct Current (DC)
</u>
It's the flow of electric charges in one direction driven by a constant voltage circuit. The intensity of the current flow is computed as
Where q is the constant flow of charge in time t
The energy of an element providing Voltage V, current I during a time t is
a. The charge can be computed by solving the first equation for q
b. The energy transferred by the battery is