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Questions in physics

[Open]When a person uses an iron to remove wrinkles from a shirt, why does heat travel from the iron to the shirt?

[Open]What is the difference between an isotope and an ion?

[Open]Why is inertia important in the laws of motion?

[Open]A 15 kg blob of "space clay" moving at a speed of 3 m/s collides with a 12.5 kg blob of "space clay" at rest. They stick together after colliding. What is their new speed? What formula is used, and how do you solve this?

[Open]If two solid substances look the same, what measurements and tests would you perform to determine whether they are actually the same?

[Open]1. An 8-kilogram bowling ball is rolling in a straight line toward you. If its momentum is 16 kg·m/s, how fast is it traveling? 2. A beach ball is rolling in a straight line toward you at a speed of 0.5 m/s. Its momentum is 0.25 kg·m/s. What is the mass of the beach ball? 3. A 4,000-kilogram truck travels in a straight line at 10.0 m/s. What is its momentum? \[ \text{Momentum} = \text{mass} \times \text{speed} = 4,000 \times 10 = 40,000 \text{ kg·m/s} \] 4. A 1,400-kilogram car is also traveling in a straight line. Its momentum is equal to that of the truck in the previous question. What is the velocity of the car? 5. Which would take more force to stop in 10 seconds: an 8.0-kilogram ball rolling in a straight line at a speed of 0.2 m/s or a 4.0-kilogram ball rolling along the same path at a speed of 1.0 m/s? 6. The momentum of a car traveling in a straight line at 20 m/s is 24,500 kg·m/s. What is the car’s mass? 7. Another pitcher throws the same baseball in a straight line. Its momentum is 2.1 kg·m/s. What is the velocity of the ball? 8. A 1-kilogram turtle crawls in a straight line at a speed of 0.01 m/s. What is the turtle’s momentum?

[Open]In a coordinate system where the x-axis is east: 1. For what range of angles is the x-component positive? 2. For what range of angles is the x-component negative?

[Open]What roles do exchange particles play in an interaction?

[Open]In the nucleus of an atom, there are 18 protons and 20 neutrons. What are the atomic number and mass number of this isotope?

[Open]Starting from rest, a 4.0-kg body reaches a speed of 8.0 m/s in 20 s. What is the net force acting on the body?