What is the final velocity of a 3 kg object that starts with a 5 m/s velocity due to a 2 N force acting over 3 seconds?

V= 13 m/s

Explanation:

We're asked to find the magnitude of the object's velocity after a force is applied for

3

s

parallel to its motion.

We'll call the direction it's moving the positive

x

-axis, and the direction of the applied force the positive

y

-axis.

The components of the initial velocity are

v

0

x

=

5

m/s

v

0

y

=

0

(It's moving at

5

meters per second in the straight line we called the

x

-axis.)

We know the object's mass is

3

kg

, and the force applied is

12

N

in the positive

y

-direction. The magnitude of the constant acceleration is thus

a

y

=

∑

F

y

m

=

12

l

N

3

l

kg

=

4

m/s

2

Since this acceleration is directed upward, and the initial

y

-velocity is

0

, we can use the kinematics equation

v

y

=

v

0

y

+

a

y

t

to find the

y

-velocity after

3

seconds.

Plugging in known values, we have

v

y

=

0

+

(

4

l

m/s

2

)

(

3

l

s

)

=

12

m/s

No acceleration was applied in the

x

-direction, so it's

x

-velocity remains

5

m/s

. The magnitude of the velocity is thus

v

=

√

(

v

x

)

2

+

(

v

y

)

2

=

√

(

5

l

m/s

)

2

+

(

12

l

m/s

)

2

=

13

m/s

it has both hydrogen and oxygen