A yo-yo, arranged as shown, rests on a frictionless surface. When a force is applied to the string as shown, the yo-yo:
A) moves to the left and rotates counterclockwise
B) moves to the right and rotates counterclockwise
C) moves to the left and rotates clockwise
D) moves to the right and rotates clockwise
E) moves to the right and does not rotate

Question

A yo-yo, arranged as shown, rests on a frictionless surface. When a force  is applied to the string as shown, the yo-yo: 
A) moves to the left and rotates counterclockwise 
B) moves to the right and rotates counterclockwise 
C) moves to the left and rotates clockwise 
D) moves to the right and rotates clockwise 
E) moves to the right and does not rotate

Quizplus · Accepted Answer

According to Newton's third law, there will be an equal and opposite force on the yo-yo by the string (11eaafba_af3c_b2d5_a7a5_431c0585b0c6_TB3976_11). Therefore, the yo-yo will move to the right (in the direction of the force) with the same acceleration as that of the force.

Now, since the force is applied at a distance from the center of mass, the yo-yo will also experience a torque, causing it to rotate counterclockwise. This is because the force tries to move the yo-yo in a straight line to the right, but the string restricts the motion by pulling upwards. As a result, the yo-yo experiences a torque directed towards the left, causing it to rotate counterclockwise. Therefore, the correct answer is option B, i.e., the yo-yo moves to the right and rotates counterclockwise.

A Yo-Yo, Arranged as Shown, Rests on a Frictionless Surface