Fundamentals of Physics - practice problems - page 3 of 50

Number of problems found: 985

Iron ball 2
What is the mass of the iron ball with a diameter of 1,0 dm? The density of iron is 7870 kg/m³.
Force gauge 2
A force gauge measured a gold necklace as Fg = 0.48 N in air and Fw = 0.45 N in water. Is it made of pure gold?
Electrical 11
An electrical device produces 4.2 MJ of work per hour at an efficiency of 53%. What is the power input of this device?
Pure gold
How much pure gold is in a 15-gram ring made of 14-carat gold? Round the result to the nearest tenth of a gram.
Rotational motion of a cylinder
Calculate the kinetic energy of a cylindrical body with radius r = 0.08 m and mass m = 1.5 kg at time t = 5 s, given that the body rotates about an axis through the centre of the cylinder with a constant angular acceleration ε = 5 rad/s², starting from re
Water + temperature
We supplied 1,365 kJ of heat to 5 kg of water initially at 20 °C. To what temperature did it heat up?
Ice + water
A rectangular ice rink measuring 60 m × 30 m had a layer of ice 3 cm thick. How many litres of water were used to create the ice?
Physics - board, lever
A wooden board weighing 0.5 kg is placed on a table. How far can it protrude over the edge of the table without falling if a weight of 0.2 kg is placed at its overhanging end?
Equality of Moments
A lever with a mass of 3 kg and a length of 2 m has weights of 5 kg and 8 kg attached at its two ends. Find the point where the lever must be supported so that it is in balance.
Large 2
A large gear has 72 teeth, a medium gear has 56 teeth, and a small gear has 27 teeth. How many revolutions will the smallest gear make when the largest gear turns 120 times?
Into the bottle
A bottle can hold water weighing no more than 1 kg. Can the same bottle hold gasoline of the same mass?
On a mass
Forces F₁ and F₂, each with a magnitude of 40 N, act on a mass point M. Their resultant has a magnitude of 60 N. Determine the angle between forces F₁ and F₂.
Ice rink
A rectangular ice rink measuring 15 m × 20 m needs to be covered with a layer of ice 4.5 cm thick. How many litres of water are needed to create the ice?
X-ray intensity
The intensity of X-ray radiation is halved when passing through a 13.5 mm thick lead layer. Determine the thickness of the lead plate that will reduce the radiation intensity to one tenth of its original value, given that the intensity decreases exponenti
On a bicycle 5
Clara left the town square on her bicycle and rode toward the city at an average speed of 20 km/h. Johnny left the same square on his bicycle 15 minutes after Clara and rode in the same direction at an average speed of 30 km/h. How long did it take Johnny
Express the unknown
Using the formula p = F ÷ S, express the unknown F.
Train - start-up
A train weighing 1,200 tonnes is supposed to reach a speed of 15 m/s in 45 s when starting up. Determine its acceleration and the magnitude of the force it must exert if the friction force is 0.005 of the train's weight.
A car acceleration
A car increased its speed from 21.6 km/h to 108 km/h over a 54-metre-long track. Determine its acceleration, assuming that the motion is uniformly accelerated.
Heating water
5 kg of water warmed up by 10 °C. How much heat did the water absorb? (Remember that 1 kg of water requires 4,200 J of heat to raise its temperature by 1 °C.)
Shear friction
How much force must be applied to a box weighing 300 kg to move it at a constant speed along a horizontal floor, if the coefficient of sliding friction between the box and the floor is 0.5?

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