Study guides, Class notes & Summaries

Why are X-rays used in medical imaging often referred to as ‘soft X-rays’? Because they have energies that are lower than gamma rays. How are X-rays produced? By rapidly accelerating or decelerating charged particles – their kinetic energy is transferred into highenergy photons How can you differentiate between X-rays and Gamma rays? X-rays and gamma rays have frequencies that overlap, so you cannot distinguish them by their wavelengths. Instead you have to use their method of prod...

Define Young’s Modulus. The Young’s Modulus of a material its ratio of tensile stress to tensile strain. It is a measure of a material’s stiffness. How is stress calculated? Stress = Force/Cross-Sectional Area How is strain calculated? Strain = Change in Length/Original Length What is the unit of stress? Pascals (Pa) or N⋅m⁻² What is the unit of strain? Strain doesn’t have a unit since it is a ratio of two lengths. What is the unit of Young’s Modulus? Pascals (Pa) or ...

What is meant by free-fall? An object is said to be falling in free-fall if the only force acting on it is gravity. This means that no resistive forces are acting (or in practice they are considered negligible). What is ‘g’? Gravitational Field Strength (in our case, on the surface of Earth). Why can the SUVAT equations be used in this experiment? The SUVAT equations can be used since the object will fall with uniform acceleration. This is because the force of gravity is constant a...

OCR AS Level Physics A H156/02 Depth in physics QUESTION PAPER AND MARK SCHEME FOR JUNE 2023 (MERGED)

A force is needed to - change an objects state of motion The combination of all forces acting on an object is called the - net force When you hold a rock at rest in your hand, you are pushing upward on it with as much force as Earth's gravity pulls down on it. The net force would be - zero on the rock The scientific unit of force is the newton-- - abbreviated N Tension is a - stretching force Weight is the force of gravity - acting downward on an object A vector is an arrow that - repre...

When you push against a wall with your fingers, they bend because they experience a force. Identify this force? - Opposite force A boxer can't hit a heavy bag with great force. Why can't he hit a piece of tissue paper in midair with the same amount of force? - Doesn't have resistance How many forces are required for an interaction? - Two One end of the rope is pulled with 100 N, while the opposite end is pulled with 100N. The tension in the rope is what? - 100 N A piece of rope is p...

What causes a moving object to keep on course? - Inertia What force exists between objects even in the absence of direct physical contact? - Field Force In the free-body diagram shown above showing a motorcycle, what can you say is happening? - The person is slowing down In the free-body diagram show above, the F N force represents... - The support force of ground on According to Newton's second law, when the same force is applied to two objects of different masses, the lighter mass wil...

1. When does conservation of energy apply? - Always 2. The conservation of energy - ____________ is a fundamental concept of physics along with the conservation of mass and the conservation of momentum. Within some problem domain, the amount of energy remains constant and energy is neither created nor destroyed. 3. A rock is perched at the very edge of the top of a very high cliff ready to fall any minute. What kind of energy does it have? - Potential Energy 4. If the rock isn't moving...

Friction - The force that always opposes motion Coefficient of friction - Force of friction divided by normal force Net force - Resultant force, the sum of all forces acting on an object Free body diagrams - Physical model of a representation of forces acting on a system 2-dimensional motion - Any motion of an object is more than one line, a plane Vector independence - Changes in one vector do not cause changes in another Projectile - Any object launched into the air with no force other th...

B - A cart rolls down inclined track and is accelerating. It fires a ball straight out of the cannon as it moves. What happens to the ball? A.) It falls in front of the cart B.) It falls right back into the cart C.) It falls behind the cart C - You drop a package from a plane flying at constant speed in a straight line. Without air resistance, what will the package do? A.) Remain vertically behind the plane B.) Remain vertically in front on the plane C.) Remain vertically under plane...