Q: A block of mass $$m$$ slides down a ramp at angle $$\theta$$ with coefficient of kinetic friction $$\mu_k. $$What is the acceleration of the block?

$$a = g(\sin \theta - \mu_k \cos \theta)$$

Q: A satellite orbits Earth at a height where the acceleration due to gravity is $$4.9\,\mathrm{m/s^2$}. If $$the radius of Earth is $$6.37 \times 10^6$\,\mathrm{m}$$, what is the satellite’s distance from the center of Earth?

$$9.01 \times 10^6$\,\mathrm{m}$$

Question 1

Which of the following best describes Newton’s 1st Law of Motion?

Accepted Answer

An object will remain at rest or in uniform motion in a straight line unless acted upon by a net external force.

Question 2

Given the system of particles shown in the first image, with masses and positions: $$2.0\,\mathrm{kg} at$$ $$(0,0)$$, $$3.0\,\mathrm{kg} at$$ $$(0,2)$$, and $$5.0\,\mathrm{kg} at$$ $$(2,2)$$, what are the coordinates of the center of mass?

Accepted Answer

$$(1.25, 1.5)$$

Question 3

A $$1200\,\mathrm{kg}$$ car traveling at $$25\,\mathrm{m/s}$$ comes to a stop in $$10\,\mathrm{s}. $$What is the magnitude of the force applied by the brakes?

Accepted Answer

$$3000\,\mathrm{N}$$

Question 4

Which of the following is an example of Newton’s 3rd Law?

Accepted Answer

Normal Force-Friction

Question 5

A $$100\,\mathrm{N}$$ box is pulled by a $$30\,\mathrm{N}$$ horizontal force. The coefficients of static and kinetic friction are $$\mu_s = 0.4$$ and $$\mu_k = 0.2. $$Will the box move?

Accepted Answer

No, because the applied force is less than the maximum static friction.

Question 6

A $$2\,\mathrm{kg}$$ mass hangs from a spring and stretches it by $$10\,\mathrm{cm}$$ from equilibrium. What is the spring constant $$k$$?

Accepted Answer

$$196\,\mathrm{N/m}$$

Question 7

A block of mass $$m is $$accelerated across a rough surface by a force $$F at an $$angle $$\phi$$ above the horizontal. The frictional force is $$f. $$What is the horizontal acceleration $$a of $$the block?

Accepted Answer

$$a = \frac{F \cos \phi - f}{m}$$

Question 8

A block of mass $$m$$ slides down a ramp at angle $$	heta$$ with coefficient of kinetic friction $$\mu_k. $$What is the acceleration of the block?

Accepted Answer

$$a = g(\sin 	heta - \mu_k \cos 	heta)$$

Question 9

Using Newton’s Law of Gravitation, derive the acceleration due to gravity $$g at $$the surface of the Earth. Which formula is correct?

Accepted Answer

$$g = \frac{G M_E}{R_E^2$}$$

Question 10

What is the orbital velocity $$v of $$the Earth around the Sun, given $$M_E = 5.97 	imes 10$$^{24}$$\,\mathrm{kg}$$, $$M_S = 1.98 	imes 10$$^{30}$$\,\mathrm{kg}$$, and $$r = 1.49 	imes 10$$^{11}$$\,\mathrm{m}$$?

Accepted Answer

$$v = \sqrt{\frac{G M_S}{r}}$$

Question 11

A $$5\,\mathrm{kg}$$ block is pulled across a horizontal surface by a $$40\,\mathrm{N}$$ force at $$30^\circ$$ above the horizontal. The coefficient of kinetic friction is $$0.3. $$What is the net horizontal acceleration? (Use $$g = 10\,\mathrm{m/s^2$})$$

Accepted Answer

$$a = 2.0\,\mathrm{m/s^2$}$$

Question 12

A satellite orbits Earth at a height where the acceleration due to gravity is $$4.9\,\mathrm{m/s^2$}. If $$the radius of Earth is $$6.37 	imes 10^6$\,\mathrm{m}$$, what is the satellite’s distance from the center of Earth?

Accepted Answer

$$9.01 	imes 10^6$\,\mathrm{m}$$

Question 13

A $$10\,\mathrm{kg}$$ box is at rest on a horizontal surface. The coefficient of static friction is $$0.5. $$What is the minimum force required to start moving the box? (Use $$g = 9.8\,\mathrm{m/s^2$})$$

Accepted Answer

$$49\,\mathrm{N}$$

Question 14

A $$0.5\,\mathrm{kg}$$ mass is attached to a spring and oscillates with a period of $$2\,\mathrm{s}. $$What is the spring constant $$k$$?

Accepted Answer

$$4.93\,\mathrm{N/m}$$

Question 15

A $$3\,\mathrm{kg}$$ object is moving at $$4\,\mathrm{m/s}$$ and comes to rest in $$2\,\mathrm{s}$$ due to friction. What is the magnitude of the frictional force?

Accepted Answer

$$6\,\mathrm{N}$$

Question 16

A $$2\,\mathrm{kg}$$ block slides down a $$30^\circ$$ incline with $$\mu_k = 0.1. $$What is its acceleration? (Use $$g = 9.8\,\mathrm{m/s^2$})$$

Accepted Answer

$$3.44\,\mathrm{m/s^2$}$$

Question 17

A $$1\,\mathrm{kg}$$ mass is attached to a spring with $$k = 100\,\mathrm{N/m}. If $$the mass is pulled $$0.2\,\mathrm{m}$$ from equilibrium and released, what is the maximum force exerted by the spring?

Accepted Answer

$$20\,\mathrm{N}$$

Question 18

A $$0.2\,\mathrm{kg}$$ ball is dropped from a height of $$10\,\mathrm{m}. $$What is its velocity just before hitting the ground? (Ignore air resistance, $$g = 9.8\,\mathrm{m/s^2$})$$

Accepted Answer

$$14\,\mathrm{m/s}$$

PHYSICS 210 Exam 2 Practice – Step-by-Step Study Guidance

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