A mass of 10 kg, initially at rest on a horizontal frictionless surface, is acted upon by a horizontal force of 25 N. The speed of the mass after it has moved 5.0 m is:

. a)  5.0 m/s 

. b)  10 m/s 

. c)  15m/s 

. d)  125 m/s 

. e)  250 m/s 


My answer:b

a = F/m = 25/10 = 5/2

v = √(2as) = √(2 * 5/2 * 5) = 5

so, how did you get B?

Well, you're definitely on the right track with the letter "b," but you might want to pump the brakes on your enthusiasm a little bit. We wouldn't want the mass to shoot off at 10 m/s like a rocket!

To find the speed of the mass, we can use the equation:
speed = (force / mass) * time

Since the mass is initially at rest, the time it takes to move 5.0 m is not given. So, we can't calculate the speed directly from the given information. Maybe we'll get a time machine for our next physics problem!

To solve this problem, we can use Newton's second law of motion, which states that the force acting on an object is equal to the mass of the object multiplied by its acceleration.

First, we need to calculate the acceleration of the object. The formula to calculate acceleration is given by:

acceleration = force / mass

In this case, the force acting on the object is 25 N, and the mass of the object is 10 kg. Plugging these values into the formula, we get:

acceleration = 25 N / 10 kg = 2.5 m/s^2

Next, we can use the equation of motion to find the final velocity of the object. The equation is:

v^2 = u^2 + 2as

Where:
v - final velocity
u - initial velocity (which is 0 m/s since the object is initially at rest)
a - acceleration (2.5 m/s^2)
s - distance traveled (5.0 m)

Plugging in the values, we get:

v^2 = 0^2 + 2 * 2.5 m/s^2 * 5.0 m
v^2 = 0 + 25 m^2/s^2
v^2 = 25 m^2/s^2

Taking the square root of both sides, we find:

v = √25 m/s
v = 5 m/s

Therefore, the speed of the mass after it has moved 5.0 m is 5.0 m/s. So, the correct answer is option a) 5.0 m/s.

To determine the speed of the mass after it has moved 5.0 m, we can use Newton's second law of motion, which states that the force acting on an object is equal to its mass multiplied by its acceleration.

In this case, the mass of the object is 10 kg, and the force acting on it is 25 N. Since the surface is frictionless, we can assume that there is no opposing force and all of the force is used to accelerate the object.

To find the acceleration of the object, we can use the equation F = ma, where F is the force and m is the mass. Rearranging this equation to solve for acceleration, we have a = F/m.

Plugging in the values, we have a = 25 N / 10 kg = 2.5 m/s^2.

Now we can use the kinematic equation v^2 = u^2 + 2as to find the final velocity (v), where u is the initial velocity (which is 0 m/s because the object starts from rest), a is the acceleration (2.5 m/s^2), and s is the distance traveled (5.0 m).

Plugging in the values, we have v^2 = (0 m/s)^2 + 2(2.5 m/s^2)(5.0 m) = 25 m^2/s^2, therefore v = sqrt(25 m^2/s^2) = 5.0 m/s.

Therefore, the correct answer is a) 5.0 m/s.