First one I believe but im not completely sure
Answer:
a. -369.36J
b. -123.9J
c. 9.52m
Explanation:
From the expression for kinetic energy
K. E=1/2mv^2
Since the mass is constant, but the velocity changes. Hence the change in kinetic energy is
K.E=1/2*19(3.6²-7.2²)
K.E= -369.36J
b. to determine the workdone by the force,we determine the distance moved.
But the acceleration is from
F=ma ,
a=f/m
a=-13/19
0.68m/s²
the distance moved is
s=v²/2a
s=3.6²/2*0.68
s=9.52m
Hence the work done is
W=force * distance
W=-13*9.52
W=-123.9J
d. the distance moved is
s=v²/2a
s=3.6²/2*0.68
s=9.52m
Answer:

Explanation:
From the question, using the expression:

where;



This is a combined intensity of 4 speakers.
Thus, the intensity of 3 speakers = 
= 2.372 W/m²
Thus;


The Coulomb’s law is expressed mathematically as:
F = k * q1 * q2 / d^2
Where,
F = force of attraction between 2 particles = 2.0 N
<span> k = Coulomb’s
constant = 8.988 * 10^9 N m^2 / C^2</span>
q = charge of the particle
d = distance between the 2 particles = 1.35 m
Since the two coins have identical charges therefore q1 =
q2 =q
F = k* q^2 / d^2
2.0 N = (8.988 * 10^9 N m^2 / C^2) * q^2 / (1.35 m)^2
q =
2.01 * 10^-5 C
<span>Therefore each coins have charges equivalent to 2.01 *
10^-5 C.</span>