Yes, she will reach the pool at a distance of 7.14m.
Answer:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
Explanation:
Answer:
The correct answer is a) The kinetic energy of the ice increases by equal amounts for equal distances.
Explanation:
The law of conservation states that the energy cannot be created nor be destroyed but can be converted from one form to another.Before the ice even starts falling we already know that it possesses energy in the form of potential energy given by P=mgh where m is the mass of the ice , g is the acceleration due to gravity and h is the height of the ice above the ground whatever that may be, since a number is not given here.As the ice falls the energy is converted from potential energy to kinetic energy. We notice one thing about the equation for the potential energy P , which is that it is not only directly proportional to h but also is linear in h as well(which is the main reason why a) is correct) which means that if the ice drops by 1 meter the potential energy it will have lost would be ΔPE=mgΔh=-mg, where Δh is the change in its height which is 1 meter here.And according to the principle of conservation of energy this energy must be converted to kinetic energy so the ΔKE=-ΔPE=mg, and this process repeats and for each meter it falls, it picks up the same amount of kinetic energy equaling mg(which is the same as the loss in PE per each meter of fall). So a 2 meter decrease in height will result in an increase in KE of 2mg, a 3 meter decrease in height will result in an increase in KE of 3mg. gain in kinetic energy only depends on the drop in height, which is true irrespective of where the ice might happen to be in its journey close to the top or the bottom. So the drop in height of lets say x at any point in the journey will result in the same increase in KE = ΔKE = mgx. Which proves part a) to be correct.
Answer:
Explanation:
Question 1
An arrow weighing 20g shortly after firing has a speed of 50m / s. Calculate the work done by the athlete. What is the potential energy of the elasticity of the tensed string?
mass m = 20g = 20/1000 = 0.02kg
speed v = 50m / s
P.E = K.E = ½mv²
P.E = ½ × 0.02 × 50²
P.E = 25 J
work done = P.E = 25J
Qestion 2
A 80 kg athlete stood on a trampoline with a coefficient of elasticity of k = 2 kN / m. As far as the edge of the trampoline lowers.
force of elasticity
F = -kx
x = F / k
in our case F will be the force of pressure or gravity
F = mg
g is gravitational acceleration, and according to Newton's second law, acceleration is force through mass - unit of force N, unit of mass kg. Acceleration either in m / s ^ 2 or N / kg
F = 80kg * 10N / kg = 800 N
x = 800N / -2000N = -0.4
The trampoline will lower, so from the level by 0.4 meters and hence this minus
Answer:
The magnitude of the force of friction equals the magnitude of my push
Explanation:
Since the crate moves at a constant speed, there is no net acceleration and thus, my push is balanced by the frictional force on the crate. So, the magnitude of the force of friction equals the magnitude of my push.
Let F = push and f = frictional force and f' = net force
F - f = f' since the crate moves at constant speed, acceleration is zero and thus f' = ma = m (0) = 0
So, F - f = 0
Thus, F = f
So, the magnitude of the force of friction equals the magnitude of my push.