Draw a free-body diagram to represent the forces acting on a kite on a string that is floating stationary in the air. Label the forces in your diagram.
The diagram has a black dot and three solid red arrows pointing away from the dot. Arrow Ft is long and pointing to the left and slightly down. Arrow Fw is also long and is a bit below a diagonal line halfway between pointing up and pointing to the right. A short arrow Fg is pointing down.
Fg is the force on the kite due to gravity.
Fw is the force exerted on the kite by the wind.
Ft is the force of tension in the string holding the kite. It must balance the vector sum of the other two forces for the kite to float stationary in the air.
A car is sliding down a hill with a slope of 20°. The mass of the car is 965 kg. When a cable is used to pull the car up the slope, a force of 4215 N is applied. What is the car’s acceleration, ignoring friction?
When objects rest on a surface, the surface applies a force to the object that supports the weight of the object. This supporting force acts perpendicular to and away from the surface. It is called a normal force,
.
When objects rest on a non-accelerating horizontal surface, the magnitude of the normal force is equal to the weight of the object:
When objects rest on an inclined plane that makes an angle
with the horizontal surface, the weight of the object can be resolved into components that act perpendicular (
) and parallel (
) to the surface of the plane. These components can be calculated using:
The pulling force that acts along a stretched flexible connector, such as a rope or cable, is called tension,
. When a rope supports the weight of an object that is at rest, the tension in the rope is equal to the weight of the object:
In any inertial frame of reference (one that is not accelerated or rotated), Newton’s laws have the simple forms given in this chapter and all forces are real forces having a physical origin.
Conceptual questions
If a leg is suspended by a traction setup as shown in
[link] , what is the tension in the rope?
In a traction setup for a broken bone, with pulleys and rope available, how might we be able to increase the force along the tibia using the same weight? (See
[link] .) (Note that the tibia is the shin bone shown in this image.)
Two teams of nine members each engage in a tug of war. Each of the first team’s members has an average mass of 68 kg and exerts an average force of 1350 N horizontally. Each of the second team’s members has an average mass of 73 kg and exerts an average force of 1365 N horizontally. (a) What is magnitude of the acceleration of the two teams? (b) What is the tension in the section of rope between the teams?
What force does a trampoline have to apply to a 45.0-kg gymnast to accelerate her straight up at
? Note that the answer is independent of the velocity of the gymnast—she can be moving either up or down, or be stationary.
(a) Calculate the tension in a vertical strand of spider web if a spider of mass
hangs motionless on it. (b) Calculate the tension in a horizontal strand of spider web if the same spider sits motionless in the middle of it much like the tightrope walker in
[link] . The strand sags at an angle of
below the horizontal. Compare this with the tension in the vertical strand (find their ratio).
(a)
(b)
. This is 2.41 times the tension in the vertical strand.
Suppose a 60.0-kg gymnast climbs a rope. (a) What is the tension in the rope if he climbs at a constant speed? (b) What is the tension in the rope if he accelerates upward at a rate of
?
Show that, as stated in the text, a force
exerted on a flexible medium at its center and perpendicular to its length (such as on the tightrope wire in
[link] ) gives rise to a tension of magnitude
.
Newton’s second law applied in vertical direction gives
Consider the baby being weighed in
[link] . (a) What is the mass of the child and basket if a scale reading of 55 N is observed? (b) What is the tension
in the cord attaching the baby to the scale? (c) What is the tension
in the cord attaching the scale to the ceiling, if the scale has a mass of 0.500 kg? (d) Draw a sketch of the situation indicating the system of interest used to solve each part. The masses of the cords are negligible.
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?