- Handouts
- Exercises
- Fundamental Concept
- Forces in Equilibrium
- Friction
- Fundamental Concept
- Rectiliner Motion
- Free Falling Bodies
- Projectile Motion
- Angular Motion
LINK: Engineering Mechanics Statics and Dynamics
Topics:
- Newton’s Law of Motion
- Conditions for Static Equilibrium
- Friction Analysis of Flexible Cables
- Properties of Sections
- Dynamics
- Kinematics
- Kinetics
- Motion at Constant Acceleration
- Free Falling Bodies
- Projectile Circular Motion
- Bombs from a plane drops at a rate of one per second. Calculate the vertical distance between two bombs after the first had dropped for 8 seconds. Assume free falling body with g=9.81 m/s2.
- a. 75.4 m
- b. 81.3 m
- c. 72.8 m
- d. 78.5 m
- Two cars A and B accelerate from a stationary start. The acceleration of A is 5 ft/s2 and that of B is 7 ft/s2. If B was originally 25 ft behind A, how long will it take B to overtake A?
- a. 8 sec
- b. 7 sec
- c. 6 sec
- d. 5 sec
- A flywheel is brought to rest up to a speed of 850 rpm in 1 minute. What is the average angular acceleration until the wheel stops?
- a. -2.32 rad/sec2
- b. -3.21 rad/sec2
- c. -4.91 rad/sec2
- d. -1.48 rad/sec2
- A car travels 120 miles to city A in 3.8 hours and then travels 220 miles to city B in 5 hours. What is the average speed of the car for the trip?
- a. 35.28 mph
- b. 37.79 mph
- c. 39.22 mph
- d. 32.34 mph
- A train with a top speed of 55 mph cannot accelerate or decelerate faster than 6 ft/s2. What is the minimum distance between two train stops in order for the train to be able to reach its top speed?
- a. 1084.52 ft
- b. 1133.62 ft
- c. 932.52 ft
- d. 1273.11 ft
- A ball is thrown vertically upward with an initial speed of 68 ft/s. How long will it take for the ball to return to the thrower?
- a. 3.76 sec
- b. 4.22 sec
- c. 5.51 sec
- d. 6.01 sec
- A ball is dropped from a height of 90 m above the ground. How long does it take to hit the ground?
- a. 5.62 sec
- b. 3.88
- c. 4.28 sec
- d. 2.32 sec
- A bicycle moves with a constant deceleration of -4 ft/s2. If the initial velocity of the bike was 15 ft/s, how far does it travel in 2.6 seconds?
- a. 20.3 ft
- b. 22.7 ft
- c. 25.5 ft
- d. 27.1 ft
- If a car traveling at 67 mph suddenly locks its brakes and skids 387.4 ft, how long will it take for the car to come to complete stop?
- a. 6.1 sec
- b. 8.2 sec
- c. 7.9 sec
- d. 9.3 sec
- A stone is dropped over a cliff and falls for 18 seconds before reaching the bottom. How high above the bottom is the cliff?
- a. 1589.2 m
- b. 1722.1 m
- c. 1821.4 m
- d. 1333.2 sec
- What is the acceleration of a body that increases in velocity from 26 m/s to 58 m/s in 12 seconds?
- a. 2.67 m/s2
- b. 3.28 m/s2
- c. 4.44 m/s2
- d. 1.28 m/s2
- Six weights of 28, 22, 48, 25, 14 and 34 lbs hang in one plane from a horizontal support at distances 3, 4, 6, 7, 10, 13 ft, respectively, from the wall. What single force would replace these six weights?
- a. 5.32 ft
- b. 4.26 ft
- c. 6.92 ft
- d. 7.17 ft
- Determine the single force that will replace the following coplanar forces: 122 N, 32o; 210 N, 112o; 166 N, 250o and 74 N, 310o.
- a. 32.5 N
- b. 28.6 N
- c. 45.2 N
- d. 49.2 N
- A girder weighing 17,000 lbs is suspended by a cable 110 ft long. What horizontal pull is necessary to hold it 9 ft from the vertical position?
- a. 1395.6 lbs
- b. 1488.8 lbs
- c. 1213.3 lbs
- d. 1522.8 lbs
- A 22 kg mass is suspended by a rope. What is the tension in the rope?
- a. 322.25 N
- b. 245.25 N
- c. 452.28 N
- d. 188.81 N
- A 75.4 kg block needs 221.6 N to move horizontally. Find the friction between the block and the plane.
- a. 0.4
- b. 0.5
- c. 0.3
- d. 0.2
- A 55 lb block is placed in a horizontal plane with coefficient of friction of 0.18. Find the force needed to move the block horizontally.
- a. 38.2 N
- b. 44.2 N
- c. 48.3 N
- d. 35.8 N
- Two forces 18 kg and 62 kg are acting at right angles. Find the resultant force.
- a. 52.3 kg
- b. 60.2 kg
- c. 64.6 kg
- d. 68.3 kg
- Two forces are acting in the following direction: F1=120 kg at 34o and F2=88 kg at 128o. Find the resultant force.
- a. 133.2 kg
- b. 148.2 kg
- c. 158.8 kg
- d. 143.8 kg
- A shot is fired at an angle of 50 deg with the horizontal at velocity of 320 fps. Calculate to the nearest, the range of projectile.
- a. 1524.9 yd
- b. 1438.3 yd
- c. 1683.8 yd
- d. 1043.9 yd
- A ball is thrown from a tower 45 m high above the ground with a velocity of 250 m/s directed 25 deg from horizontal. How long until the ball hit the ground.
- a. 25.3 sec
- b. 21.1 sec
- c. 28.3 sec
- d. 18.9 sec
- A 50 kg block resting on a 20 deg inclined plane from the horizontal, has a coefficient of friction of 0.60. Find the force parallel to the inclined that must be applied to cause impending motion down the plane. Use g=9.81 m/s2.
- a. 108.8 N
- b. 115.2 N
- c. 128.3 N
- d. 138.7 N
- A 30 kg box is released from rest and travel down from a 30 deg inclined plane. If the coefficient of friction is 0.28, what will be the velocity of the box when it travels 15 m from its initial position?
- a. 6.28 m/s
- b. 7.84 m/s
- c. 8.71 m/s
- d. 5.33 m/s
- A 120 kg box is dragged 85 m down the sidewalk at constant velocity. What work is done if the coefficient of the sliding friction between the box and the pavement is 0.28?
- a. 28 kJ
- b. 32 kJ
- c. 25 kJ
- d. 20 kJ
- A truck weighing 5 kips moves a slope of 25 deg. What is the force generated by the engine if the truck is accelerating at a rate of 8 ft/sec2? Assume f=0.12.
- a. 2511.3 lbs
- b. 2687.8 lbs
- c. 2438.1 lbs
- d. 2811.5 lbs
- A man weighs himself in an elevator. When the elevator is at rest, he weighs 160 lbs; when the elevator starts moving upwards he weighs 210 lbs. How fast is the elevator accelerating, assuming constant acceleration?
- a. 9 ft/sec2
- b. 10 ft/sec2
- c. 11 ft/sec2
- d. 12 ft/sec2
- An elevator weighing 4300 lbs attain an upward velocity of 25 fps in 8 sec with uniform acceleration. The tension in the supporting cable is _____.
- a. 4050.22 lbs
- b. 4717.31 lbs
- c. 4830.18 lbs
- d. 4322.76 lbs
- A force of 50 N causes an acceleration of 3 m/s2 when acting on an 8 kg mass. What is the frictional force also acting?
- a. 26 N
- b. 24 N
- c. 28 N
- d. 30 N
- How much does a 55 lb object weight on the moon (gmoon = 5.32 ft/sec2)?
- a. 7.09 lbs
- b. 8.30 lbs
- c. 10.32 lbs
- d. 9.09 lbs
- What force is acting if a 85 slugs object accelerates at 10 ft/sec2?
- a. 800 lb
- b. 750 lb
- c. 850 lb
- d. 900 lb
Forces in Equilibrium
A 10 kg weight is suspended by a cable from a ceiling. If a horizontal force of 5.8 kgs is applied to the weight, the cable will make an angle with the vertical equal to ____?
SOLUTION:
Friction
The value of force P (parallel to the incline) required to prevent the 500 kg block to slide down the 30 degrees incline, (assuming coefficient of static friction to be 0.25) is ____.
SOLUTION:
Rectiliner Motion
Two cars are travelling at the same speed of 80 kph in the same direction on the level road with car A 100 meters ahead of car B. Car A slows down to make a turn, decelerating at 2.13 m/s2. In how many seconds will car B overtake car A.
SOLUTION:
Free Falling Bodies
A ball is dropped down a well and six second later, the sound of the splash is heard. If the velocity of sound is estimated at 330 m/s, what is approximate depth of this well?
SOLUTION:
Projectile Motion
A ball is thrown so that it is just clears a fence 12 ft high and 50 ft away. If it left the thrower’s hand 5 ft above the ground and at an angle of 60 degrees with the horizontal. What was the initial velocity of the ball in ft/sec? Neglecting air resistance.
SOLUTION:
Angular Motion
A flywheel rotates at a velocity of 200 rpm and decelerates constantly at a rate of 2 rad/sec2. Compute the time the flywheel will take before it fully stops and the number of revolutions it make.
SOLUTION: