(HELP!! 10pts) a train travels 75km in 1hr, and then 68km in 2hrs. what is its average speed?
1 answer:
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Hello!
Find the acceleration using the formula a = (vf - vi) / t where:
vf = final velocity
vi = initial velocity
t = time
Plug in the points above:
vf = +10 m/s
vi = +20 m/s
t = 5 sec
(10 - 20) / 5 = -10 / 5 = -2 m/s²
Answer:
a) F = -1035.385 N
b) Backwards
c) s = 15.60 m
Explanation:
Given information
= Initial Speed of Car = 15.0 m/s
= Final Speed of Car = 9.00 m/s
= Breaking Time = 1.30 s
= Mass of Car = 1040 kg
Part (a)
To find the force exerted on the car we use the following formula
Where
= Force = unknown
= Mass of Car = 1040 kg
= Acceleration of Car / Deceleration of Car = unknown
To find the force (F) we need to first find the deceleration rate (a)
To find the deceleration rate we use the following formula
Inputting the given values
To find the force
Part (b)
Since the value of F is negative this means the the force was opposite the direction of motion, hence the force was backwards.
Part (c)
To find the total distance the car moved while braking we use the following formula
Where
= distance traveled
Inputting the values given