a 4.0kg block of wood is pulled along a horizontal ground from rest and a force of 15N is required to produce acceleration of 2.0metres per second squared . what should the magnitude of the force be in order to pull the block of wood at constant speed of 5.0m/s on the same horizontal ground
A. 5N B. 7N C. 8N D. 10N
Ff = friction force
15 - Ff = m a = 4 * 2 = 8
so Ff = 15 - 8 = 7 Newtons friction
then no acceleration so a = 0
so
F = Ff = 7 N
To determine the magnitude of the force required to pull the block of wood at a constant speed of 5.0 m/s, we can use Newton's laws of motion.
First, let's recall Newton's second law, which states that the net force acting on an object is equal to the mass of the object multiplied by its acceleration:
F = m * a
In this case, the given mass of the block of wood is 4.0 kg, and the given acceleration required to produce a speed of 2.0 m/s is 2.0 m/s^2. Thus, we can calculate the force required to produce the initial acceleration:
F_initial = m * a
= 4.0 kg * 2.0 m/s^2
= 8.0 N
Now, since we want to maintain a constant speed of 5.0 m/s, we know that the net force acting on the block of wood must be zero. This means that the force required to overcome any opposing forces (such as friction) should be equal to the force that was initially used to accelerate the block of wood. Therefore, the magnitude of the force required to pull the block of wood at a constant speed of 5.0 m/s is also 8.0 N.
So, the correct answer is C. 8N.