Fundamentals of Physics - practice for 14 year olds
Number of problems found: 369
- Heat energy
Energy is measured using the unit Joule (J). Temperature is measured using the unit degree Celsius °C). To increase the temperature of 1 liter of water by 1°C, 4200 J of heat energy is required. (a) Kelly wants to increase the temperature of 2 liters of w - The temperature 39
The temperature outside is currently 10 degrees, dropping at an average rate of 2 degrees per hour. If the temperature continues to drop at this rate, what will the temperature be in 7 hours? - The temperature 38
The temperature has been dropping 2 degrees every hour, and the temperature at 10:00 AM was -15 degrees Fahrenheit. At what time was the temperature 0 degrees Fahrenheit? - Braking 83146
A car of mass m=1t moves at a speed v0=54 km/h. What braking force must be exerted to bring the car to a stop in 10 seconds, and how far will the car travel in this time?
- Distilled 83093
The 50% salt solution must be diluted with distilled water to make 20 liters of 35% solution. How many liters of original solution and how many liters of water do we need? - Penetrates 83078
A hammer with a mass of 600 g hits the head of a nail at a speed of 5 m/s. If the nail penetrates 3 cm into the wall, what is the average resistive force of the masonry? - Overcoming 83076
A battering ram weighing 400 g falls from a height of 3 m. Upon impact, the stake hits a depth of 60 cm. What is the average force overcoming the soil resistance? - Concerning 83022
A man with a mass of 80 kg crosses at a speed of 5 m/s through the car of a train traveling at 15 m/s. Indeed, the kinetic energy of a man: and, concerning the car b, relative to the surface of the earth, if the man is traveling in the direction of travel - Interpretation 83015
A cargo boat with a total weight of 4,500t sailed from the river to the sea. Calculate by how many tons it is possible to increase the weight of the cargo on the boat at sea so that the draft remains the same as in the river. The density of river water is
- Ostrava 83008
A truck with a speed of 45 km/h left Ostrava. When he had passed 15 km, a car with a 90 km/h speed came behind him. How long does a car catch up with a truck take? How far from Ostrava? - Supporting 82880
Roman and Mathias made a swing in the park by taking a 5 m-long pole and supporting it in the middle. Roman, weighing 52 kg, sat down at the left end. Where should Mathias sit to achieve balance if he weighs 60 kg? Enter the distance measured in meters fr - Resistance 82714
A load of 23.5 ohm is connected to an ideal voltage source of 30V, and a current of 1.2A passes through the circuit. Determine the magnitude of the source's internal resistance and the short-circuit current. - A raft
I want to build a raft, and I have beams with a square section with side a=20cm and length l=2m, wood density 670 kg/m³. I will connect 10 beams - what is the volume of the raft and its weight? How deep will a raft sink in water (water density 1000kg/m³)? - Traveled 82618
The car traveled a distance of 120 km in 1 hour 50 minutes. The first part of this track traveled at a speed of 50 km per hour, and the second part traveled at a speed of 75 km per hour. The 10 minutes the driver needed to fill the gas are included in the
- Suspended 82617
A round steel weight (ρ1=7800 kg/m3) is suspended on a thread and immersed in water (ρ2=1000 kg/m3). The volume of the weight is 1dm³. With what force is the thread stretched? - Motorcyclist 82445
Motorcyclist Arnošt begins to move on his motorcycle in a uniformly accelerated motion with an acceleration of 1.6 m/s². At what time will it reach a speed of 50 km/h? What distance will it travel at this time? - Consider 82380
The pool is 50m long. The first swimmer swims across it in the 60s and the second in the 40s. Both start at the same time and on the same side. The faster swimmer turns around at the end and swims back. When will he meet the slower swimmer? Swimmers move - Calculating 82316
From the formula for calculating thermal energy Q=m*c*t, express t and calculate by how many °C 2kg of water must be heated to increase its energy by 126kJ - Acceleration 82217
The car has a speed of 5 m/s and accelerates to 35 m/s in 12 seconds. Calculate the acceleration of the car at a speed of 34.5 m/s.
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