2d Force dynamic practice problems
a - Mrs. Helios pushes a 2 tonne car with a force of 1 000 N [Fwd 5" Dwn] on a flat road. Mr. MilkyWay assists by pulling with 500 N [Fwd 12" Up]. The axel friction provides an average of 10 N of force and drag provides approximately 5 N of force. Determine the time it takes to accelerate the car from rest to a comfortable cruising speed of 2 m/'s. Do not bother to determine the Normal force for this question since there is no sliding friction (we have wheels). (do I of 2) B - Mr. Ra pushes a 800 kg sled from rest with 1600 N [Fwd 10 Dwn]. Ms. Sol assists by pulling with 800 N [Fwd 150 Up]. The coefficient of kinetic friction is 0.250. Determine the velocity of the sled after 2.5 s. This time you will need to find the normal force first. (do 1 of 2) y - Ms. Mercury pushes a 25 kg buffing machine forward with a force of 30 lbs [Forward 20' Down]. The coefficient of friction is 0.275. Determine time it takes to reach the desired speed of 1.5 m's from rest. (do 1 of 2) A - Ms. Venus pulls a sleigh massing I tonne with 220 lbs [East 30 Up]. Ms. Luna helps her out by pushing with 165 lbs [East 10 Down]. Determine the coefficient of friction if they maintain a uniform velocity of 1.5 m/s. (do 1 of 2) A - Mr Uranus of mass of 75 kg sits on his butt and slides down an icy hill with a coefficient of friction 0.200 and sloped at an angle of 45". Determine the average drag force if he accelerates from rest to 20 m's over a 50 m distance. H - Ms. Vulcan has a mass of 50 kg and Mr. X. weighs 187 Ibs. Together they hang from a bungee cord of stiffness 75 N/m. a) If they are at rest and at the equilibrium position then determine how much the bungee cord has been stretched. b) If they currently have an instantancous acceleration of 0.5 y's upwards, then what is the current stretch of the bungee cord? c) If they currently have an instantaneous acceleration of 0.1 g's downwards, then what is the current stretch of the bungee cord? 5 - Mr Orion sets up the following apparatus with blocks and strings. What are the tensions in string A and string B if the block has a mass of 10 kg and currently stationary and in equilibrium, Remember A and B have vector components! Solve by making two equations with two unknowns. (do 1 of 2) 450 30 String A String B 10 kg G Ms Sagittarius sets up the following apparatus with blocks and strings. What is the coefficient of static friction between 10 kg block and the table surface if the system at rest and in equilibrium where acceleration is zero and nothing is currently moving? Remember string B has vector components. (do 1 of 2) 150 1350 String A String B 10 kg block 5 kg block - Ms. Ceres pulls a 100 kg sled with a force of 1 000 N [South 30 Up] along a flat snowy pathway with a coefficient of friction of 0.200. The sled is attached to her friend Mr. Eris whom is skiing and masses 50 kg. a) Determine the acceleration of the sled and wagon and the time it will take to reach a cruising speed of 4 m/'s. b) Now add 3 more objects to the string train: sled 15 kg, toboggan 10 kg and a snowboard 5 kg and determine the new acceleration and time. E - Dr. Mars has a mass of 75 kg and weighs 735 N or 165 lbs on the Earth. a) What is his weight in N and Ibs on Jupiter where the acceleration due to gravity is 24.8 m/s'? b) If he weighs 63.1 Ibs on the planet Martes then determine the gravitational force field strength on Martes. (extra credit) 0- Ms. Saturn compresses a spring 80 cm using 200 Ibs of force. Determine the spring constant (stiffness) in N/m. She then uses the spring in a cylinder it to fire a 150 g baseball with a launch angle of [ East 450 Up] from an initial height of 1.5 m. Determine the how far away the baseball will land from her if she compressed the launcher 50 cm and the average internal friction force of the launcher is 6.818 N. (do 1 of 2) K - Mr. Neptune picks up his ballet dance partner Ms. Pluto who masses 45 kg and overcoming gravity tosses her upwards and forwards with an average applied force of 220 lbs [Fwd 60 Up] for 0.500 s. Gravity is acting on Ms. Pluto as well. Determine her final velocity and then determine how far away she will land if he releases her from a height of 2m. (do I of 2)
