Physical Quantities and Measurement

Fiery is delivering a coffee order across a flat plane. The coffee cup has a mass of 0.5 kg, and it is accelerated uniformly from rest to 5 m/s over a distance of 10 m using a scooter. Which physical quantity best describes the total work done on the coffee cup during this process?

• 12.5 J

• 25 J

• 62.5 J

• 125 J

A weather balloon filled with helium is released into the atmosphere. Its initial volume is 5 m³, pressure is 1 atm, and temperature is 300 K. As it rises, the temperature drops to 250 K, and the pressure decreases to 0.5 atm.

Which quantities affect the final volume of the balloon?

• Initial pressure

• Final pressure

• Final temperature

• Initial temperature

• Gravitational acceleration

Mona pours 500 mL of tea at 90°C into a metal cup with a mass of 200 g. She measures the initial temperature of the cup at 25°C. Assuming the system is isolated and reaches thermal equilibrium at 50°C, Mona calculates that the specific heat capacity of the cup is 400 J/(kg·°C). Her calculation is correct.

• True
• False

A scientist is conducting an experiment to study the relationship between temperature and heat transfer in a metal rod. The rod is heated at one end while the other end remains in contact with a heat sink. Explain how you would measure physical quantities like thermal conductivity and specific heat capacity in this scenario. What methods would you use to ensure accurate and consistent measurements throughout the experiment?

Alex is building a model of a skyscraper for an exhibition. The actual height of the skyscraper is 320 meters, and Alex is making a model at a scale of 1:400. What should be the height of the model?

• 0.4 meters
• 1.6 meters
• 0.8 meters
• 1.2 meters

During a physics class, two students are comparing the mass of a hollow steel cylinder and a solid aluminum cylinder using a digital weighing scale. The steel cylinder weighs 2.5 kg, and the aluminum cylinder weighs 3.0 kg. After some modifications, they measure again and find that the steel cylinder weighs 2.2 kg while the aluminum cylinder weighs 3.5 kg. Which of the following statements are correct? (Select all that apply)

• The aluminum cylinder has consistently been heavier than the steel cylinder.

• The steel cylinder lost more mass than the aluminum cylinder gained.

• The combined mass of the cylinders after the modification is greater than their combined mass before the modification.

• The steel cylinder lost exactly 0.3 kg in mass.

A student uses a graduated cylinder to measure the volume of an irregularly shaped rock. Initially, the cylinder contains 200 mL of water. After placing the rock into the water, the level rises to 250 mL. The rock's volume is 0.25 liters. True or False?

• True
• False

A particle accelerator is used to produce a beam of particles traveling at a velocity close to the speed of light. Due to time dilation, the lifespan of the particles extends by a factor of 3 compared to their lifespan at rest, which is 2 microseconds. Fill in the blank: The particles' observed lifespan in the accelerator is __________ microseconds.

In a volcanic region, scientists monitor the temperature of a lava flow to predict its behavior and potential risks. They use pyrometers to measure the temperature of the molten rock, which ranges from 700°C to 1,200°C. If the pyrometer malfunctions due to intense heat and emits inaccurate readings, what alternative methods could the scientists use to determine the temperature? Discuss the challenges of temperature measurement in such extreme conditions and the significance of accurate readings for public safety.