Newton's Laws of Motion Problem

In summary, the conversation discusses the mass and inclination of a wedge, as well as its given acceleration, and uses Newton's Law for a System to find the acceleration of a block relative to the wedge and the normal force. A question is posed about an incorrect answer and whether the blocks are in free fall.
  • #1
rajumahtora
18
0

Homework Statement


Mass of Block A = 1 kg
Mass of Wedge B = 2 kg
Inclination of Wedge is 37°
and Cos 37° = 4/5
The wedge is given an acceleration of 5 ms-2
Find -
1. Acceleration of Block wrt Wedge
2. Normal Force
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Homework Equations



Newton's Law for a System (hereby referred as NLS)
∑fext = m1a1+m2a2...+mnan

The Attempt at a Solution



Let the Acceleration of Block wrt Wedge be λ along the inclination.
In Y axis, there is only one Ext force i.e. The gravity and ∑fnet in Y direction is m1g+ m2g = (m1+ m2)g
Therefore in Y axis using Newton's Law for a System,
mAaA + mBaB = (m1+ m2)g
but in Y axis , aA = 0
and ab in Y axis = λsinθ + aAcos 90
= λsinθ + 0
= λsinθ
Therefore, mBaB = (m1+ m2)g
1 (λsin(θ)) = (1 + 2)g
λ sin 37° = (3)10
λ(3/5) = 30
λ = 50
but using pseudo force, λ = 2 ms-2 which is correct answer in the Answer Key
Where am I going Wrong?
Please Help
 

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  • #2
Is wedge B being given an acceleration horizontally to the left or right?

Assuming then no friction block A will also be sliding down the inclined wedge B.
 
  • #3
rajumahtora said:
in Y axis using Newton's Law for a System,
mAaA + mBaB = (m1+ m2)g
Are you assuming that the blocks are in free fall? I would have guessed the wedge is supported somehow.
 

FAQ: Newton's Laws of Motion Problem

1. What are Newton's Laws of Motion?

Newton's Laws of Motion are three fundamental principles that explain the behavior of objects in motion. They were formulated by Sir Isaac Newton in the 17th century and are considered the foundation of classical mechanics.

2. What is the first law of motion?

The first law of motion, also known as the law of inertia, states that an object at rest will remain at rest and an object in motion will continue in a straight line at a constant speed, unless acted upon by an external force.

3. What is the second law of motion?

The second law of motion states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass. In other words, the larger the force applied to an object, the greater its acceleration will be, and the more massive the object, the less it will accelerate.

4. What is the third law of motion?

The third law of motion, also known as the law of action and reaction, states that for every action, there is an equal and opposite reaction. This means that when one object exerts a force on another object, the second object will exert an equal but opposite force on the first object.

5. How are Newton's Laws of Motion used in real life?

Newton's Laws of Motion are used in many aspects of our daily lives, from driving a car to playing sports. They are also essential in fields such as engineering and aerospace, where understanding and applying these laws is crucial in designing and building structures and vehicles that can withstand different forces and movements.

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