Astone of mass 0.55 kilograms is released and falls to the ground. measurements show that the stone has a kinetic energy of 9.8 joules at the point of impact with the ground. what is the stone's velocity when it hits the ground?
a.6.3 meters/seconds
b.7.2 meters/seconds
c.8.1 meters/seconds
d.9.3 meters/seconds

The correct answer is option a.

Explanation:

Kinetic energy is the energy of the object due to its motion.

Mass of the stone = m = 0.55 kg

Velocity of the stone = v

Kinetic energy of the stone when it hits the ground = K.E = 9.8 Joules

Kinetic energy is given as:

6.3 m/s the stone's velocity when it hits the ground.

6.3 m/s ≈ 6 m/s

The closest option to our answer is option a.

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g