Physics: Weight, Mass, and Density Concepts

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Questions and Answers

What is the weight of a man with a mass of 75 kg in Newtons?

735 N

What is the mass of Teacher John in slugs and in lbm if he weighs 180 pounds?

slugs: 5.4; lbm: 180

What is the mass of a woman on a planet with gravity of 4 m/s² if her mass on Earth is 54 kg?

54 kg

What would be the weight on the moon of an object that weighs 52 pounds on Earth?

15.47 lbm Signup and view all the answers

What volume will 150 g of mercury occupy if its density is 13.6 g/cm³?

11.03 cm³ Signup and view all the answers

What is the weight density of a board measuring 2" x 6" x 5' that weighs 15 lbs and 4 oz?

0.12 lb/ft³ Signup and view all the answers

What is the density of a system consisting of 2 kg of water and 120 liters of steam in a 50-liter vessel?

17.31 kg/m³ Signup and view all the answers

What is the density of lubricating oil with a specific gravity of 0.92?

920 kg/m³ Signup and view all the answers

What is the specific gravity of a plastic cylinder that is 100 mm long and has a mass of 1 kg?

5.092 Signup and view all the answers

What is a woman's systolic blood pressure of 160 mm Hg in lb/in²?

3.12 lb/in² Signup and view all the answers

What is the absolute pressure of a fluid in kPa if the gauge indicates 12 kPa and the outside pressure is 110 kPa?

122 kPa Signup and view all the answers

What is the absolute pressure inside a condenser if the vacuum gauge reads 65 kPa and the barometer indicates 1.013 bar?

53 kPa Signup and view all the answers

What is the water pressure at the bottom of the sea at a depth of 3600 m with a specific gravity of 1.03?

36.39 MPa Signup and view all the answers

What is a worker's body temperature of 40°C in °F?

104°F Signup and view all the answers

What is the absolute temperature in Rankine if the air temperature is 85°F?

565.67 R Signup and view all the answers

What is the temperature change in Kelvin if a room air conditioner causes a temperature change of −5.2°C?

5.2 K Signup and view all the answers

What is the temperature change in °F for water entering an electric heater at 30°C and leaving at 38°C?

14.4°F Signup and view all the answers

What is the velocity of water through the nozzle of a garden hose if the inner radius is 1.0 cm and water flows at 2.0 m/s?

10 m/s Signup and view all the answers

What is the volume flow rate of air leaving a duct if 1 cubic meter per second of air enters with a density of 1.2 kg/m³?

0.94 m³/s Signup and view all the answers

What is the density of a casting of an alloy weighing 74 g with a thickness of 0.125 inch and a diameter of 1.75 in?

15.028 g/cm³ Signup and view all the answers

What is the allowable depth a submarine can descend to withstand a pressure of 1.2 × 10^7 Pa?

1193.5 m Signup and view all the answers

What is the absolute pressure in the condenser in bars when the condenser vacuum gauge reads 706 mm Hg at a barometric pressure of 755 mm Hg?

0.065 bars Signup and view all the answers

What is the conversion of a pressure of 25 mm water to mm Hg?

1.84 mm Hg Signup and view all the answers

What is the gauge pressure of air in an automobile tire, converted from 0.21 lb/ft² to torr?

0.075 torr Signup and view all the answers

What is a furnace temperature of 4500 °R expressed in °C?

2226.67 °C Signup and view all the answers

What is the temperature in Kelvin when the temperature reaches 41°C?

314 K Signup and view all the answers

What is the temperature of a patient reading 41°C in Fahrenheit?

105.8 °F Signup and view all the answers

What is the temperature difference of 54.0 °F expressed in Kelvin?

30 K Signup and view all the answers

What is the velocity of water leaving a smaller pipe connected to a larger pipe with given areas?

2 m/s Signup and view all the answers

How fast is water traveling as it leaves a garden hose that fills a 25-L wastebasket in 120 s with a radius of 1.00 cm?

66.3 cm/s Signup and view all the answers

What is the average speed of blood traveling in arteries given the aorta velocity and dimensions?

19.53 cm/s Signup and view all the answers

Study Notes

Weight and Mass

Weight is the force exerted on an object due to gravity. It is measured in Newtons (N).
Mass is the amount of matter in an object. It is measured in kilograms (kg).
Weight = Mass x Acceleration due to gravity (g)
- On Earth, g ≈ 9.8 m/s²

Density

Density is the mass per unit volume of a substance.
Density = Mass / Volume
Specific gravity is the ratio of the density of a substance to the density of water at 4°C.
- Specific gravity = Density of substance / Density of water
- Density of water ≈ 1 g/cm³ or 1 kg/m³

Pressure

Pressure is the force per unit area.
Pressure = Force / Area
Gauge pressure is the difference between the absolute pressure and the atmospheric pressure.
Absolute pressure is the total pressure at a point, including the atmospheric pressure.
Vacuum pressure is the pressure below atmospheric pressure.

Temperature

Celsius (°C) and Fahrenheit (°F) are commonly used scales for measuring temperature.
Kelvin (K) is the absolute temperature scale.
0 K = -273.15 °C
°F = (9/5)°C + 32
°C = (5/9)(°F - 32)

Fluid Mechanics

Flow rate is the volume of fluid flowing per unit time.
Flow rate = Volume / Time
Velocity is the speed of fluid flow.
Velocity = Distance / Time
Continuity equation: For an incompressible fluid, the mass flow rate at any point in a pipe is constant.
- Mass flow rate = Density x Area x Velocity

Energy

Energy is the capacity to do work.
Potential energy is the energy stored due to an object's position.
Kinetic energy is the energy stored due to an object's motion.
Work = Force x Distance

Examples

Example 1: Weight of a man
- Mass of man = 75 kg
- Weight = 75 kg x 9.8 m/s² = 735 N
Example 2: Volume of mercury
- Mass of mercury = 150 g
- Density of mercury = 13.6 g/cm3
- Volume = Mass / Density = 150 g / 13.6 g/cm3 = 11.03 cm³
Example 3: Flow rate of air
- Flow rate of air entering duct = 1 m³/s
- Density of entering air = 1.2 kg/m³
- Density of leaving air = 1.18 kg/m³
- Applying continuity equation:
  - Mass flow rate entering = Mass flow rate leaving
  - Density_entering x Area_entering x Velocity_entering = Density_leaving x Area_leaving x Velocity_leaving
  - Velocity_leaving = (Density_entering x Area_entering x Velocity_entering) / (Density_leaving x Area_leaving)
  - Velocity_leaving = (1.2 kg/m³ x 0.2 m x 0.15 m x 1 m³/s) / (1.18 kg/m³ x 0.175 m x 0.125 m)
  - Velocity_leaving = 1.36 m/s
- Flow rate of leaving air = Area_leaving x Velocity_leaving = 0.175 m x 0.125 m x 1.36 m/s = 0.03 m³/s
Example 4: Potential energy of suitcase
- Mass of suitcase = 30 kg
- Height = 35 m
- Potential energy = Mass x Acceleration due to gravity x Height = 30 kg x 9.8 m/s² x 35 m = 10.3 kJ

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Description

This quiz covers fundamental concepts related to weight, mass, density, pressure, and temperature in physics. Understand the relationships between these physical quantities and their implications in real-world scenarios. Perfect for students seeking to reinforce their knowledge in introductory physics.