To generate both lift and thrust, birds must use their wings as a cross between a wing (lifting surface) and a propeller by accelerating fluid both down and backward. To control the direction of the force on their wings, birds vary two parameters: the stroke-plane angle and the pronation angle (see the figure below). What…

If you are accelerating down much less than the acceleration due to gravity, the tension on the bottom string is much less than the tension of the top string*. Because the tension is greater at the top, that string will break first. At which point the string is most likely to break? So, the wire…

The principle for hydraulic lifts is based on Pascal’s law for generating force or motion, which states that pressure change on an incompressible liquid in a confined space is passed equally throughout the liquid in all directions. Hydraulic lifts provide controlled and precision force. How do you solve hydraulic lift problem? What is the formula…

The pulley, a simple machine, helps to perform work by changing the direction of forces and making easier the moving of large objects. When thinking of pulleys, most people think of the type of pulley that allows a person to redirect the direction of a force. How do you find the pulley in physics? If…

Helium has 0.0114 pounds per cubic foot. For a one cubic foot helium filled balloon , gravity pulls the down on the helium with a force of 0.0114 pounds while the air pushes up with a force equal to the weight of the air the helium displaced, or 0.0807 pounds. How do you calculate helium…

Clearly, even our average H2 molecule (1.92 km/sec) can escape. So quickly, all the hydrogen would escape from the Moon to space. What is hydrogen escape? Definition. The term hydrodynamic escape refers to the removal of gas from the atmosphere of a planet possessing a strong gravity field by the viscous drag of an escaping…

List and describe the two steps for solving conceptual problems. Analyze and Solve. Analust the conceptual problem and then solve it. How do you solve a conceptual physics problem? Focus on the Problem. Establish a clear mental image of the problem. A. Describe the Physics. Refine and quantify your mental image of the problem. A.…

Rotational collisions conserve angular momentum The two objects exert equal, but opposite angular impulses upon each other to maintain the total angular momentum of the colliding system. An example of this would be a ball colliding with a stick that rotates about its end as shown in Figure 3. How do you solve rotation problems…

Today it is generally believed that calculus was discovered independently in the late 17th century by two great mathematicians: Isaac Newton and Gottfried Leibniz. How do you solve physics problems in calculus? Is calculus based physics hard? If you understand calculus, calc-based physics will be easier. You won’t need to memorize many formulas and will…

Conservation of linear momentum : Pi=Pf. Initial momentum Pi=0 as the gun and the bullet do not move. Final momentum Pf=mgVg+mbvb. ∴ 0=mgVg+mbvb. ⇒0=8Vg+(0. 01)(400) ⇒∣Vg∣=0. 5 m/s. What is the formula for the ballistic pendulum? (M +m)v2, where M is the mass of the pendulum, m is the mass of the ball, and v…

a) Acceleration of a block on Horizontal Surface: When body is moving under application of force P, then kinetic friction opposes its motion. Let, a is the net acceleration of the body, from the figure ma = P – Fk ⇒ a=P−Fkm. What happens if the friction blocks are sliding? Even if the object is…

There are 3 forms of energy during a bungee jump, kinetic (KE = 0.5mv^2), gravitational potential (GPE = mgh) and elastic potential (EPE = 0.5kx^2). Energy is conserved throughout, and it’s assumed none is lost as heat due to air resistance. How does bungee jumping relate to physics? Bungee jumping is a thrilling, spectacular and…

Forces Due to Friction (and Newton’s Third Law) When you push a heavy box, it pushes back at you with an equal and opposite force (Third Law) so that the harder the force of your action, the greater the force of reaction until you apply a force great enough to cause the box to begin…

USAPhO is sometimes used to refer to just the semi-final exam, as it is the last of the national physics exams (and is thought of as analogous to USAMO). How many people take the F MA? F = ma exam Approximately 6,000 students take this first exam, which consists of 25 multiple choice questions to…

The archer holds the feather end of the arrow against the string while pulling it back. Releasing the string thrusts the arrow forward with the elastic force of the bow. The elastic potential energy of the bow is converted to the kinetic energy of the arrow. How does gravity affect archery? When the archer releases…

For this question you just simply need to apply the formula for torque which is r×F where r = (3-0)i +(2-0)j+(3-0)k and F=(2i-3j+4k) , just do the normal cross product calculations which will give you 17i -6j-13k. This is your final torque expression. How do you solve torque problems in physics? What are some examples…

A coaxial cable (described in Section 29.1) is a straight conductor surrounded by a concentric, cylindrically shaped conductor. Coaxial cables are widely used as conductors for current. For example, currents produced in the pickup of a stereo turntable generally travel to the amplifier through a coaxial cable. How does a coaxial cable work? Coaxial cable…

The video asks students to predict when a bungee jumper experiences maximum acceleration. The answer is at the very bottom of the jump. This is often counter-intuitive as the velocity at this point is almost zero. As velocity is directional the maximum change occurs at the point the direction changes. What is the physics behind…

The amount of force a hydraulic cylinder can generate is equal to the hydraulic pressure times the effective area of the cylinder. (Effective Area is the surface area of the piston face in square inches.) FORMULAS: Force = psi x Area of Piston. How do you solve hydraulic lift problem? How does a hydraulic jack…

The magnitude of the acceleration will be the same for each object. How do you solve pulley problems in physics? How do you find the tension between two objects in physics? We know that the force of tension is calculated using the formula T = mg + ma. How do you find the contact force…