Newton's second law Knowledge-Based Practice

Questions

1. 1.

   A constant net force $F$ produces an acceleration of $6.0\text{ m/s}^2$ when applied to an object of mass $m_1$, and an acceleration of $3.0\text{ m/s}^2$ when applied to an object of mass $m_2$. What acceleration does the same force produce when the two objects are fastened together?

   • A) $1.5\text{ m/s}^2$
   • B) $2.0\text{ m/s}^2$
   • C) $4.5\text{ m/s}^2$
   • D) $9.0\text{ m/s}^2$
2. 2.

   A 6.0 kg crate is pushed up a frictionless incline of 30° by a constant force of 48 N applied parallel to the incline. Taking $g = 10\text{ m/s}^2$, what is the magnitude of the acceleration of the crate?

   • A) 8.0 m/s$^2$
   • B) 13 m/s$^2$
   • C) 5.0 m/s$^2$
   • D) 3.0 m/s$^2$
3. 3.

   A 3.0 kg cart on a frictionless horizontal track is connected by a light string passing over an ideal pulley to a hanging 2.0 kg block. Taking $g = 10\text{ m/s}^2$, what is the magnitude of the acceleration of the cart when the system is released?

   • A) 2.0 m/s²
   • B) 4.0 m/s²
   • C) 6.7 m/s²
   • D) 10 m/s²
4. 4.

   A 4.0 kg box is pulled across a smooth, frictionless horizontal floor by a 24 N force directed at an angle of 60° above the horizontal. What is the magnitude of the acceleration of the box?

   • A) $1.5\text{ m/s}^2$
   • B) $5.2\text{ m/s}^2$
   • C) $6.0\text{ m/s}^2$
   • D) $3.0\text{ m/s}^2$
5. 5.

   A constant horizontal force of 24 N pushes two blocks of masses $m_1 = 2.0\text{ kg}$ and $m_2 = 4.0\text{ kg}$ that are in contact on a frictionless horizontal surface, with the force applied directly to $m_1$. What is the magnitude of the contact force exerted by block $m_1$ on block $m_2$?

   • A) 6.0 N
   • B) 8.0 N
   • C) 12 N
   • D) 16 N
6. 6.

   An object of mass $m$ experiences an acceleration $a$ when acted upon by a net force $F$. If the net force is increased to $3F$ and the mass is reduced to $\frac{1}{2}m$, what is the new acceleration in terms of $a$?

   • A) $\frac{1}{6}a$
   • B) $\frac{3}{2}a$
   • C) $3a$
   • D) $6a$
7. 7.

   Two perpendicular horizontal forces of magnitudes 12 N and 16 N act simultaneously on a 4.0 kg block resting on a frictionless horizontal floor. What is the magnitude of the block's acceleration?

   • A) 1.0 m/s²
   • B) 3.0 m/s²
   • C) 5.0 m/s²
   • D) 7.0 m/s²
8. 8.

   A constant net force of 60 N acts on an object, causing its speed to increase from 10 m/s to 25 m/s in 5.0 s. What is the mass of the object?

   • A) 20 kg
   • B) 12 kg
   • C) 8.0 kg
   • D) 4.0 kg
9. 9.

   A crane lifts a 250 kg crate vertically upward with a constant acceleration of $1.2\text{ m/s}^2$. Taking the acceleration due to gravity as $g = 9.8\text{ m/s}^2$, what is the tension in the crane cable?

   • A) 2750 N
   • B) 2450 N
   • C) 2150 N
   • D) 300 N
10. 10.

    A horizontal pulling force of 35 N is applied to a 5.0 kg crate moving along a horizontal surface where a constant kinetic friction force of 10 N opposes the motion. What is the magnitude of the acceleration of the crate?

    • A) 5.0 m/s²
    • B) 7.0 m/s²
    • C) 9.0 m/s²
    • D) 2.0 m/s²

Answers and step-by-step solutions appear after you finish the test.