Answer:
The velocity of the train is 82.8 km/h
Explanation:
The equation for the position of the train and the car is as follows:
x = x0 + v · t
Where:
x = position at time "t".
x0 = initial position.
v = velocity.
t = time.
First, let´s calculate the distance traveled by the car in 60 s (1/60 h). Let´s place the origin of the frame of reference at the front of the train when it starts to pass the car so that the initial position of the car is 0 (x0 = 0 m):
x = 0 m + 72 km/h · (1/60) h
x = 1.2 km.
Then, if the whole train passes the car at that time, the position of the front of the train at that time will be 1.2 km + 0.18 km = 1.38 km.
Then using the equation of position we can obtain the velocity:
x = x0 + v · t
1.38 km = 0 m + v · (1/60) h
1.38 km / (1/60) h = v
v = 82.8 km/h
The velocity of the train is 82,8 km/h
The same result could be obtained using the rear of the train. You only have to identify where the rear is at t = 0 and where it is at t = 60 s.
Try it!
Answer:
Explanation:
The formula to find average acceleration is a=Δv/Δt.
Convert 216 km/hr to m/s
216 km/hr * 1000 m/km * 1 hr/60 mins * 1 min/60 secs = 60 m/s
So a= (60 m/s)/(5.0*10^-3) = 12000 m/s^2
Put that into scientific notation to get 1.2*10^4 m/s^2
Answer: D. The object would have an acceleration of 6 m/s/s to the right.
Explanation:
I got it right on USA test prep
F=ma
So a=F/m
if acceleration is zero, resultant force is also zero.
Answer:
2.5
Explanation:
25-22.5n= will give you 2.5
