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PH 105-003/4 -- Wednesday, September 12, 2007. Clicker problem: Two strings are attached to a 10 kg box on a frictionless surface. 1 2 3 4 5 6 7 8. One pulls with 20 N north, the other pulls with 20 N east. The magnitude of the acceleration, rounded to the nearest integer, is:.
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PH 105-003/4 -- Wednesday, September 12, 2007 Clicker problem:Two strings are attached to a 10 kg box on a frictionless surface. • 1 • 2 • 3 • 4 • 5 • 6 • 7 • 8 One pulls with 20 N north, the other pulls with 20 N east. The magnitude of the acceleration, rounded to the nearest integer, is:
PH 105-003/4 ---- Wednesday, Sept 12, 2007 Chapter 5 F = ma PH 105
PH 105-003/4 ---- Friday, Sept 14, 2007 Chapter 5 -- review Newton’s 2nd law F = ma (1stis special case a=0) N’s 3rd law: FAB = FBA Free Body diagrams include all forces on 1 object Half-Atwood’s Machine Inclined plane: derive a = g sin q 10/9/2014 • PH 105
PH 105-003/4 ---- Monday, Sept 17, 2007 Chapter 5 -- finish Free Body diagrams Example 5-4 (static equilib.) Apparent weight Friction Half-Atwood’s Machine 10/9/2014 • PH 105
PH 105-003/4 ---- Wednesday, Sept 19, 2007 (exam Friday, homework this PM) Chapter 5 -- finish Review friction: f = m n Half-Atwood’s Machine: (1) for what m2 does it slip? (2) What is a after it slips? 10/9/2014 • PH 105
Clicker question: A team of Alaskan huskies pulls a sled of weight 4000 N at a constant speed of 2 m/s across snow, exerting a force 200 N on the sled. What is the coefficient of friction of the sled? Formula: {1} Value: {2} x 10{3} 10/9/2014
vf = vi + a Dt xf = xi + vi t + ½ a t2 f = m n a = v2/r 2aDx = v2 – vi2 vAC = vAB + vBC Clicker question: A team of Alaskan huskies pulls a sled of weight 4000 N at a constant speed of 2 m/s across snow, exerting a force 200 N on the sled. What is the coefficient of friction of the sled? Formula: {1} Value: {2} x 10{3} Put on line 1 in real exam: Which equation would you use to solve this problem? 10/9/2014 PH 105
A team of Alaskan huskies pulls a sled of weight 4000 N at a constant speed of 2 m/s across snow, exerting a force 200 N on the sled. What is the coefficient of friction of the sled? Formula: {1} Value: {2} x 10{3} Clicker Question • 0 • 1 • 2 • 3 • 4 • 5 • 6 • 7 On line 2 in real exam: mantissa of value
A team of Alaskan huskies pulls a sled of weight 4000 N at a constant speed of 2 m/s across snow, exerting a force 200 N on the sled. What is the coefficient of friction of the sled? Formula: {1} Value: {2} x 10{3} Clicker Question • 0 • 1 • 2 • 3 • 4 • 5 • 6 • 7 On line 3 in real exam: exponent of value (ignore sign)