ANSWER:
F(h)= 230 N is the horizontal force you will need to move the pickup along the same road at the same speed.
STEP-BY-STEP EXPLANATION:
F(h) is Horizontal Force = 200 N
V is Speed = 2.4 m/s
The total weight increase by 42%
coefficient of rolling friction decrease by 19%
Since the velocity is constant so acceleration is zero; a=0
Now the horizontal force required to move the pickup is equal to the frictional force.
F(h) = F(f)
F(h) = mg* u
m is mass
g is gravitational acceleration = 9.8 m/s^2
200 = mg*u
Since weight increases by 42% and friction coefficient decreases by 19%
New weight = 1+0.42 = 1.42 = (1.42*m*g)
New friction coefficient = μ = 1 - 0.19 = 0.81 = 0.81 u
F(h) = (0.81μ) (1.42 m g)
= (0.81) (1.42) (μ m g)
= (0.81) (1.42) (200)
= 230 N
Acceleration = (change in speed) / (time for the change)
Change in speed = (end speed) - (start speed) = (15 m/s - 7 m/s) = 8 m/s
time for the change = 2 minutes = 120 seconds
Acceleration = (8 m/s) / (120 seconds)
Acceleration = 0.067 m/s²
So we want to know how can we detect infrared rays without an instrument. Infrared rays or heat, are a part of electromagnetic spectrum. We have specialized nerve cells in our skin called thermoreceptors that can detect differences in temperature that are produced by infrared part of EM spectrum.
speed of the car = 27 m/s
speed of truck ahead = 10 m/s
relative speed of car with respect to truck

relative deceleration of car

now the distance before they stop with respect to each other is given by



so it will come at the same speed of truck after 20.6 m distance and hence it will not hit the truck as the distance of the truck is 25 m from car
Part b)
Distance traveled by car before it stops is given by



so it will stop after it will cover total 52.1 m distance
Part c)
time taken by the car to stop



now the distance covered by truck in same time

now after the car will stop its distance from the truck is

<em>so the distance between them is 11.5 m</em>
Answer:
a) 3.33 ns
b) Water distance = 0.75 m
Glass distance = 0.66 m
Diamond distance = 0.41 m
Explanation:
We take the speed of light, c = m/s.
Speed = distance/time
Time = distance/speed
a)

t = 3.33 ns
b)
Refractive index, n = speed of light in vacuum / speed of light in medium





Thus, the distance traveled in the same time is numerically equal to the reciprocal of the refractive index.
For water n = 1.333
d = 1/1.333 = 0.75 m
For glass n = 1.517
d = 0.66 m
For diamond n = 2.417
d = 0.41 m