# Physics equations/04-Dynamics: Force and Newton's Laws/Q:forces

## A

1 A mass with weight (mg) of 44 newtons is suspended symmetrically from two strings. The angle between the two strings (i.e. where they are attached to the mass) is 60 degrees. What is the tension in the string?

 a) 16.7 N. b) 19.2 N. c) 22.1 N. d) 25.4 N. e) 29.2 N.

2 A mass with weight (mg) equal to 25 newtons is suspended symmetrically from two strings. Each string makes the (same) angle of 69 degrees with respect to the horizontal. What is the tension in each string?

 a) 10.1 N. b) 11.6 N. c) 13.4 N. d) 15.4 N. e) 17.7 N.

3 A 4.5 kg mass is sliding along a surface that has a kinetic coefficient of friction equal to 0.37 . In addition to the surface friction, there is also an air drag equal to 29 N. What is the magnitude (absolute value) of the acceleration?

 a) 5.8 m/s2. b) 6.6 m/s2. c) 7.6 m/s2. d) 8.8 m/s2. e) 10.1 m/s2.

4 A mass with weight (mg) 7.3 newtons is on a horzontal surface. It is being pulled on by a string at an angle of 30 degrees above the horizontal, with a force equal to 3.94 newtons. If this is the maximum force before the block starts to move, what is the static coefficient of friction?

 a) 0.37 b) 0.44 c) 0.53 d) 0.64 e) 0.77

## B

1 A mass with weight (mg) of 48 newtons is suspended symmetrically from two strings. The angle between the two strings (i.e. where they are attached to the mass) is 30 degrees. What is the tension in the string?

 a) 24.8 N. b) 28.6 N. c) 32.9 N. d) 37.8 N. e) 43.5 N.

2 A mass with weight (mg) equal to 29 newtons is suspended symmetrically from two strings. Each string makes the (same) angle of 60 degrees with respect to the horizontal. What is the tension in each string?

 a) 12.7 N. b) 14.6 N. c) 16.7 N. d) 19.3 N. e) 22.1 N.

3 A 2.1 kg mass is sliding along a surface that has a kinetic coefficient of friction equal to 0.46 . In addition to the surface friction, there is also an air drag equal to 14 N. What is the magnitude (absolute value) of the acceleration?

 a) 6.4 m/s2. b) 7.3 m/s2. c) 8.4 m/s2. d) 9.7 m/s2. e) 11.2 m/s2.

4 A mass with weight (mg) 5.3 newtons is on a horzontal surface. It is being pulled on by a string at an angle of 30 degrees above the horizontal, with a force equal to 3.05 newtons. If this is the maximum force before the block starts to move, what is the static coefficient of friction?

 a) 0.34 b) 0.4 c) 0.49 d) 0.58 e) 0.7