Constant acceleration equations (SUVAT)

In summary, a stone is projected horizontally from a 49m high sea cliff with a speed of 20ms^-1. The only thing that needs to be calculated is the time it takes for the stone to drop vertically, which can be found using the constant-acceleration equation with an initial velocity of 0 m/s.
  • #1
sharbie
2
0

Homework Statement


A stone is projected horizontally from the top of a vertical sea cliff 49m high, with a speed of 20ms^-1. Neglecting air resistance, calculate:
The time that it takes to reach the sea.



Homework Equations


v² =u²+2as
t=v-u/a
t=d/s


The Attempt at a Solution


I'm not sure whether i should be calculating v-final velocity via v² =u²+2as and using that to find t, ie. t=v-u/a
or simply
t=d/s

can anybody enlighten me please? thanks
 
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  • #2
sorry about the layout by the way, don't know what happened there- first time user :smile: anyway, would much appreciate help please :smile:
 
  • #3
The only thing you're concerned with (for the problem, as stated) is the time it takes to drop vertically. And, since it's projected horizontally, it doesn't matter what the initial velocity is. Hint: v_0y = 0.

You need to use the constant-acceleration equation that relates initial position, final position, acceleration, time, and initial velocity (0 m/s).EDIT: You don't need (for this problem) to find out the final velocity.
 

Related to Constant acceleration equations (SUVAT)

1. What are the SUVAT equations used for?

The SUVAT equations, also known as the kinematic equations, are used to describe the motion of an object experiencing constant acceleration. They can be used to calculate the displacement, velocity, and acceleration of an object at a given time.

2. What does "SUVAT" stand for?

SUVAT is an acronym for the variables used in the constant acceleration equations: S (displacement), U (initial velocity), V (final velocity), A (acceleration), and T (time).

3. How are the SUVAT equations derived?

The SUVAT equations are derived from the basic equations of motion, which state that the displacement of an object is equal to its initial velocity multiplied by time, plus half of its acceleration multiplied by the square of time.

4. What are the units used in SUVAT equations?

The units used in SUVAT equations depend on the system of units being used. In the SI system, displacement is measured in meters (m), velocity in meters per second (m/s), acceleration in meters per second squared (m/s^2), and time in seconds (s).

5. Can the SUVAT equations be used for non-constant acceleration?

No, the SUVAT equations are only valid for objects experiencing constant acceleration. For non-constant acceleration, more complex equations, such as those derived from calculus, are needed to accurately describe the motion of an object.

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