54,236 views
1 vote
1 vote
}

Use g = -9.8 m/s
1. If an object is allowed to fall freely toward the earth, what will be its displacement
after 2.0 seconds?

User Pkolodziej
by
2.7k points

1 Answer

16 votes
16 votes

Answer:


(-19.6)\; {\rm m}, assuming that the object was initially not moving.

Step-by-step explanation:

Under the assumptions, the acceleration
a of this object will be constant:
a = g = (-9.8)\; {\rm m\cdot s^(-2)}.

The initial velocity
u of this object will be
0\; {\rm m\cdot s^(-1)} since this object was initially not moving:
u = 0\; {\rm m\cdot s^(-1)}.

Let
x denote the displacement of this object. This object has been accelerating for
t = 2.0\; {\rm s}. Apply the SUVAT equation
x = (1/2)\, a\, t^(2) + u\, t to find the displacement of this object in that much time:


\begin{aligned}x &= (1)/(2)\, a\, t^(2) + u\, t \\ &= (1)/(2) * (-9.8)\; {\rm m\cdot s^(-2)} * (2.0\; {\rm s})^(2) + 0\; {\rm m\cdot s^(-1)} * 2.0\; {\rm s} \\ &= (1)/(2) * (-9.8) * 2.0^(2) \; {\rm m} \\ &= (-19.6)\; {\rm m}\end{aligned}.

In other words, the displacement of this object would be
(-19.6)\; {\rm m} (displacement is negative since this object is now below where it initially was.)

User Zwlayer
by
3.1k points