Light receptors within the eye transmit messages to the brain. This produces the familiar sensations of color. Newton observed that color is not inherent in objects. Instead, the surface of an object reflects some colors and absorbs all the others. We perceive only the reflected colors.
An ultrasound? it’s commonly used to make pictures of internal organs and to check to see if someone is pregnant
Answer:
A) Force = 2303.925 N in the negative x-direction
B) F ≈ 143998.28 N
C) Ratio = 62.5
Explanation:
A) Since the brakes are the only thing making the van to come to a stop, then first of all, we will calculate the force (in a component along the direction of motion of the car) that the brakes will apply on the van.
Let's find the deceleration using Newton's law of motion formula;
v² = u² + 2as
where;
v = final velocity,
u = initial velocity,
s = displacement
a = acceleration
We are given;
u = 87.5 km/h = 24.3056 m/s
s = 125 m
v = 0 m/s
Thus;
0 = (24.3056)² + 2a(125)
- (24.3056)²= 250a
a = - 24.3056²/250
a = - 2.363 m/s²
Now, force = mass × acceleration
We are given mass = 975 kg
Thus;
Force = 975 x (-2.363)
Force = 2303.925 N in the negative x-direction
B) formula for kinetic energy is
KE = ½mv²
KE = ½(975)(24.3056)²
= 287996.568288 J
Work done on impact = F x 2
Thus;
2F = 287996.568288
F = 287996.568288/2
F ≈ 143998.28 N
C) Ratio = Force on car/braking force = 143998.284/2303.925 = 62.5
Question: a body of mass 30 kg moving north a velocity of 0.5 ms-1 subjected of 15 N North for 2.7 s. Calculate the final velocity of the body.
Answer:
14 m/s
Explanation:
From the question,
F = ma......................... Equation 1
make a the subject of the equation
a = F/m....................... Equation 2
Given: F = 15 N, m = 30 kg.
Substitute these values into equation 2
a = 15/3
a = 5 m/s².
Using,
a = (v-u)/t.................... Equation 3
Where v = final velocity, u = initial velocity, t = time.
Given: u = 0.5 m/s, t = 2.7 s and a = 5 m/s²
Substitute these values into equation 3
5 = (v-0.5)/2.7
(v-0.5) = 5×2.7
v-0.5 = 13.5
v = 13.5+0.5
v = 14 m/s
, meaning that its initial KE is non-zero.
