The answer is actually 1 & 17, maybe you meant to put 1&17 as option b
Answer:
Friction between the box and the floor is 25N to the left
Explanation:
There are two forces acting on the box along the horizontal direction:
- The force of push applied by the worker, in the forward direction, F
- The force of friction, 
, acting in the opposite direction (backward)
So the net force acting on the box is
According to Newton's second law of motion, the net force on an object is equal to the product between its mass (m) and its acceleration (a), so we can write:
And so
However, in this case the box is moving at constant speed; this means that its acceleration is zero:
Therefore we have:
Which means
And since we are told that
This means that the force of friction is also 25 N:
The final velocity of the composite object is 6/5 m/sec.
<h3>
what is velocity?</h3>
- Velocity is the direction at which an item is moving and serves as a measure of the rate at which its location is changing as seen from a certain point of view and as measured by a specific unit of time (for example, 60 km/h northbound).
- In kinematics, the area of classical mechanics that deals with the motion of bodies, velocity is a basic idea.
- A physical vector quantity called velocity must have both a magnitude and a direction in order to be defined.
- Speed is the scalar absolute value (magnitude) of velocity; it is a coherent derived unit whose quantity is measured in metres per second (m/s or m/s1) in the SI (metric system).
To learn more about the topic, refer to the following link:
brainly.com/question/80295?source=archive
#SPJ4
Answer:
48 hours
Explanation:
Using the formula,
R/R' = 2ᵃ/ᵇ..................... Equation 1
Where R = Original amount, R' = Radioactive remain, a = Total time, b = half life.
Given: b = 24 hours,
Let: R = X, then R' = X/4.
Substitute into equation 1
X/(X/4) = 2ᵃ/²⁴
4 = 2ᵃ/²⁴
2² = 2ᵃ/²⁴
Equating the base and solving for a
2 = a/24
a = 24×2
a = 48 hours.
Hence the time = 48 hours
