Braking acceleration class 10?
Hello,
Does anyone know how to solve this problem?
A body moves with constant acceleration a = -3 m/s^2. At the beginning of the motion, it has a position of s = 24 m and an initial velocity of v = 6 m/s.
a) Where and at what time does the body reverse its direction of motion?
b) After what time does it reach its starting position again?
Since I'm writing a test on this topic on Monday, I would be very grateful if someone could explain to me how to solve something like this.
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Since this is an accelerated movement, you first write the two equations for movement on the paper:
Now you think: it is in demand for the change of direction of movement (time and place). At the moment when the direction of movement changes, v=0 must be (you have to stand first in order then to be able to drive in the other direction). So with Equation 2, you get the time for how long it takes:
(Attention here: a is negativewhy time t then at the end is greater than zero)
You can use the time calculated here in Formula (1) to determine the location “s”.
To determine the time you need to return to the initial position, you solve the equation:
This gives (with the set of zero product) two solutions for time t – and one of them is the time required (the other is the start time t=0)
Note for testing: The result for the time you are looking for is not quite surprising when you compare it with the time until the turn.