(a)
consider the motion of the tennis ball. lets assume the velocity of the tennis ball going towards the racket as positive and velocity of tennis ball going away from the racket as negative.
m = mass of the tennis ball = 60 g = 0.060 kg
v₀ = initial velocity of the tennis ball before being hit by racket = 20 m/s
v = final velocity of the tennis ball after being hit by racket = - 39 m/s
ΔP = change in momentum of the ball
change in momentum of the ball is given as
ΔP = m (v - v₀)
inserting the above values
ΔP = (0.060) (- 39 - 20)
ΔP = - 3.54 kgm/s
hence , magnitude of change in momentum : 3.54 kgm/s
1. b An element is the simplest form of a substance.
3. a Atoms are comprised of particles such as protons, neutrons, and electrons.
2. c Atoms are tiny pieces of matter.
4. d Phase refers to the state of matter: gas, liquid, and solid.
The kinetic energy of an object is given by
KE = 0.5mv²
where m is the mass and v is the velocity.
To calculate the change in kinetic energy...
Initial KE:
KEi = 0.5mVi²
where Vi is the initial velocity.
Final KE:
KEf = 0.5mVf²
where Vf is the final velocity.
ΔKE = KEf - KEi
ΔKE = 0.5mVi² - 0.5mVf²
ΔKE = 0.5m(Vf²-Vi²)
Given values:
m = 16kg
Vi = 25m/s
Vf = 20m/s
Plug in the given values and solve for ΔKE:
ΔKE = 0.5×16×(20²-25²)
ΔKE = -1800J
Dependent / Response Variable: factor or condition in a experiment that changes as a result of the independent variable; often called the responding variable. ... Constant: factors or conditions in an experiment that are kept the same in as trials of the experiment. Control: a set up without the variable being tested.
