In Problems 70 through 72 you are given the dynamics equations that are used to solve a problem. For each of these, you are to
a. Write a realistic problem for which these are the correct equations.
b. Draw the free-body diagram and the pictorial representation for your problem.
c. Finish the solution of the problem.
70. -0.80n = (1500 kg)ax
n - (1500 kg)(9.80 m/s2) = 0
71. T - 0.20n - (20 kg)(9.80 m/s2) sin 20°
= (20 kg)(2.0 m/s2)
n - (20 kg) (9.80 m/s2) cos 20° = 0
72. (100 N) cos 30° - fk= (20 kg)ax
n + (100 N) sin30° - (20 kg)(9.80 m/s2) = 0
fk= 0.20n
Want to see the full answer?
Check out a sample textbook solutionChapter 6 Solutions
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics, Books a la Carte Edition; Student Workbook for Physics for Scientists ... eText -- ValuePack Access Card (4th Edition)
- In a head-on, inelastic collision, a 4,000-kg truck going 10 m/s east strikes a 1,000-kg car going 20 m/s west. (a) What is the speed and direction of the wreckage? (b) How much kinetic energy was lost in the Collision?arrow_forward(a) A cat with a mass of 850 kg in moving to the right with a constant speed of 1.44 m/s. What is the total force on the cat ? (b) What is the total force on the cat if it is moving to the left?arrow_forwardYour forehead can withstand a force of about 6.0 kN before fracturing, while your cheekbone can only withstand about 1.3 kN. a. If a 140 g baseball strikes your head at 30 m/s and stops in 0.0015 s, what is the magnitude of the ball’s acceleration? b. What is the magnitude of the force that stops the baseball? c. What force does the baseball apply to your head? Explain. d. Are you in danger of a fracture if the ball hits you in the forehead? In the cheek?arrow_forward
- A soccer player kicks a stationary 0.425 kg ball giving it a speed of 13.7 m/s. The player’s foot is in contact with the ball for 0.097 second. What is the average force when the player kick the ball? a. 6 N b. 5.8 N c. 60 N d. 84 Narrow_forwardYou push a 40.0 kg box across a floor at a constant velocity of 1.00 m/s. the coefficient of kinetic friction is ?k = 0.15. a. Draw a free body diagram. b. Decide of which type of problem-solving technique you need, inertial or dynamic. c. Determine the value of your push in newtonsarrow_forwardWhile playing basketball in PE class, Michael Angelo lost his balance after making a lay-up and colliding with the padded wall behind the basket. His 56-kg body decelerated from 9.5 m/s to 0 m/s in 0.34 seconds. Determine the force acting upon Michael Angelo's body. a. F = 2354.2 N b. F = 1564.7 N c. F = 1897.3 N d. F = 3564.2 Narrow_forward
- 3. A crate with mass m=5kg is accelerated at 25 m/s2 bya force F along a 10.0 m horizontal plane with coefficient of kinetic friction of 0.2 which meets a frictionless inclined plane with 35° angle above the horizontal. a. Find the velocity of the crate just before it reaches the inclined plane. b. How far does the crate reach along the inclined plane before it starts to slides down? c. How much force F is required to the do work on the crate to accelerate along the horizontal plane?arrow_forward13. After completing a jump. Ice skater glides across slick ice, slowed by 60 N frictional force. The coefficient of kinetic friction for her skate on ice is 0.1. What is the mass of the ice skater? 0 kg 15 kg 30 kg 60 kg 14. You kick a soccer ball on a level playing surface at angle of 56 degrees to discover that it landed 54 meters away from you. How fast did you kick it? a. 3 m/s b. a. b. c. d. 12 m/s c. 24 m/s d. 36 m/s e. None of these are correctarrow_forwardDelfa falls from a building and is caught by the diving superhero. Assuming that Delfa with a mass of 55 kg is falling at a terminal velocity of 70 m/s, 11. Determine the average force is exerted on her if it takes 0.1 s to slow her to a stop. a. 32500 N c. 38500 N b. 34500 N d. 36500 N 12. If Lois can withstand a maximum acceleration of 7g, determine the minimum time should it take Superman to stop her after he begins to slow her down? a. 1.12s c. 1.22 s b. 1.02 s d. 1.32 sarrow_forward
- b. While you are on your way coming to lectures you met Mr. Coffie and his wife; Mr. Coffie has a body mass of 100kg, the body mass of Mrs. Coffie is 50kg more. Assuming these two individuals have the same line of application; draw their forces in the following scenarios: 1. Mr. Coffie and Mrs. Coffie are moving in the same direction. ii. Mr. Coffie and Mrs. Coffie are moving in the opposite direction. ii. What steps are you going to use to determine the magnitude of their resultant when they are moving in the same direction? iv. What steps are you going to use to determine the magnitude of their resultant when they are moving in the opposite direction?arrow_forwardPlease don't write in a paper. I can't understand handwritten. 3. A ball with a mass of 0.6 kg hits a wall with a velocity of 10 m/s. Wall applies 4000 N force to the ball and it turns back with 5 m/s velocity. Find the time of ball-wall contact. 4. A ball was thrown horizontally from the edge of the table at a velocity of 4 m/s. If the table is 2 m high, what is the ball's velocity just before it hits the ground? 5. A ball was thrown horizontally from the ed of the table at a velocity of 4 m/s. If the table is 2 m high, what is the ball's velocity just before it hits the ground?arrow_forward7. A car of mass m, is speeding up on level ground with an acceleration as a function of time given by d(t) = a1 where az and t, are non-zero constants. The mass of the car stays the same (it is a constant). a. Write Newton's 2nd Law for a system that only includes the car. b. Integrate your Newton's 2nd Law equation with respect to time fromt = 0 to t = 2t1 to determine an expression that relates the impulse exerted on the car to the mass and acceleration of the car. c. Determine the magnitude of the impulse on the car from t = 0 to t = 2t1. Note: this is the vector sum of all the impulses or "net impulse" acting on the car during this time period.arrow_forward
- Glencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillUniversity Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice University
- Physics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning