The atomic number Z of an element is the number of protons it contains (and in an atom it is equal to the number of electrons). The mass number M is close to the mass of one mol of the substance but it is defined as the number of protons and neutrons in the nucleus of the atom; there, the main mass of the atom is contained. Hence, N=M-Z=74-36=38(since M counts both protons and neutrons while Z only protons). Thus, it has 38 neutrons.
==> The total mass resting on the table is (5 kg + 3 kg) = 8 kg.
==> The total weight of that mass is (8 kg) x (9.8 m/s) = 78.4 newtons
==> The boxes are stacked. So the table doesn't know if the weight on it is coming from one box, 2 boxes, 3 boxes, or 100 boxes in a stack. The table only knows that there is a downward force of 78.4 newtons on it.
==> The table stands in a Physics classroom, and it soaks up everything it hears there. It knows that every action produces an equal and opposite reaction, and that forces always occur in pairs.
Ever since the day it was only a pile of lumber out behind the hardware store in the rain, the table has known that in order to maintain the good reputation of tables all over the world, it must resist the weight of anything placed upon it with an identical upward force. This is the normal thing for all good tables to do, up to the ultimate structural limit of their materials and construction, and it is known as the "normal force".
So the table in your question provides a normal force of 78.4 newtons. (d)
Answer:
602.27 kg
Explanation:
The computation of the largest mass of cargo the balloon can lift is shown below:-
Volume of helium inside the ballon= (4 ÷ 3) × π × r^3
= (4 ÷ 3) × 3.14 × 6.953
= 1406.19 m3
Mass the balloon can carry = volume × (density of air-density of helium)
= 1406.19 × (1.29-0.179)
= 1562.27 kg
Mass of cargo it can carry = Mass it can carry - Mass of structure
= 1562.27 - 960
= 602.27 kg
Answer:
D.
Explanation:
Red light has wavelengths around 620 to 750 nm.
