Non-Equilibrium Applications of Newtons Laws

[IAmSparticus]

1. In the drawing, the weight of the block on the table is 388 N and that of the hanging block is 175 N. Ignore all frictional effects, and assuming the pulley and the cord to be massless. Find the acceleration of the two blocks as well as the tension in the cord


2. Fnet = mass of the object * acceleration



3. The force acting on the hanging block is gravity which has a magnitude of 9.8 m/s/s, and the mass is 17.86 kg. So the net force, which is just equal to the gravitational force, would be 175 N, which is incorrect. What am I doing wrong?

 

[Redbelly98]

There is another force acting on the hanging block. Do you see what it is, from looking at the diagram?

Hint: what stops the hanging block from falling as if it were dropped?

 

[tomcue]

Hello there,

I can provide some insights on the non-equilibrium applications of Newton's Laws in this scenario. Firstly, let's break down the problem into smaller parts to better understand the forces at play.

1. The weight of the block on the table is 388 N, and it is experiencing a downward force due to gravity. This force can be calculated using the formula F = m * g, where m is the mass of the block and g is the acceleration due to gravity (9.8 m/s^2). So, the mass of the block would be 388 N / 9.8 m/s^2 = 39.6 kg.

2. The hanging block is experiencing two forces - the downward force due to gravity (175 N) and the upward tension force from the cord. The net force acting on the hanging block can be calculated as Fnet = ma, where m is the mass of the block and a is the acceleration of the block. In this case, the net force would be 175 N - T, where T is the tension in the cord.

3. Now, according to Newton's Second Law, the net force acting on an object is equal to its mass multiplied by its acceleration (Fnet = ma). So, we can equate the equations from steps 1 and 2 to find the acceleration of the hanging block. This would give us the equation 175 N - T = 17.86 kg * a. We can rearrange this equation to get a = (175 N - T) / 17.86 kg.

4. To find the tension in the cord, we can use the equation of motion for the hanging block, which is Fnet = ma. In this case, the net force acting on the hanging block is the tension in the cord (T) minus the weight of the block (175 N). So, we get the equation T - 175 N = 17.86 kg * a. We can substitute the value of a from step 3 into this equation to find the tension in the cord.

I hope this helps in solving the problem and understanding the application of Newton's Laws in non-equilibrium scenarios. It is important to consider all the forces acting on the objects and use the appropriate equations to find the unknown quantities. If you are still having trouble, I suggest seeking assistance from a physics tutor or consulting a textbook for more practice problems.