1)The speedometer on a car’s dashboard measure
average speed
average velocity
instantaneous acceleration
instantaneous speed
2)A car moving on a straight road increases its speed from 30 m/s to 50 m/s in a distance of 180 m. If the acceleration is constant, how much time elapses for the auto to move this distance?
9 s
3.6 s
6 s
4.5 s
3)
a = (50-30)/t = 20/t
180 = 30t + a/2 t^2
180 = 30t + 10t
t = 4.5
check:
30(9/2) +20/9 (9/2)^2 = 135 + 20/9*81/4 = 180
1) The speedometer on a car's dashboard measures the instantaneous speed of the car.
To understand how the speedometer works, we need to know that speed is calculated by dividing the distance traveled by the time taken. The speedometer uses a combination of a speed sensor and a rotating magnet in the car's transmission system to measure the speed at which the wheels are rotating. This measurement is then converted into the speed of the car and displayed on the dashboard.
2) To find the time elapsed, we can use the equation:
v = u + at
Where:
v = final velocity = 50 m/s
u = initial velocity = 30 m/s
a = acceleration (which is constant)
t = time elapsed
We are given the initial velocity, final velocity, and the distance. We can use the equation:
v^2 = u^2 + 2as
Where:
s = distance = 180 m
Rearranging the equation, we have:
2as = v^2 - u^2
Substituting the given values, we get:
2a(180) = (50)^2 - (30)^2
360a = 2500 - 900
360a = 1600
a = 1600 / 360
a = 4.44 m/s^2 (approximately)
Now, we can substitute this value of acceleration into the first equation:
50 = 30 + 4.44t
20 = 4.44t
t = 20 / 4.44
t = 4.50 s
Therefore, the time taken for the car to move the distance of 180 m is approximately 4.50 seconds.
3) It seems like the question is incomplete. Please provide the missing information or complete the question and I will gladly assist you.