FMJ 2025 Entrance Exam - Physics
Resolution of the Physics questions from the FMJ 2025 entrance exam.
0:00 | Introduction
0:36 | QUESTION 36 - A freight train traveled the route from Santa Fé do Sul to Jundiaí, indicated on the map, passing through Itirapina at 9:20 am and through Campinas at 1:20 pm on the same day. Knowing that the distance between Itirapina and Campinas is 120 km, that the distance between Campinas and Jundiaí is 40 km, and that the train maintained a constant speed on the route from Itirapina to Jundiaí, the time this train arrived in Jundiaí was at:
(A) 2:10 pm.
(B) 2:20 pm.
(C) 2:50 pm.
(D) 3:10 pm.
(E) 2:40 pm.
4:34 | QUESTION 37 - The figure shows a block on a frictionless horizontal surface, attached to one end of a spring with a spring constant of k, whose other end
is attached to a wall. The figures show three positions of the block: (1) position x = 0, in which the spring is not deformed, (2) position x = 2L, in which the block is held at rest, and (3) position x = L, in which the block passes for the first time after being released from position x = 2L.
Considering that there was no loss of mechanical energy during the movement of the block, the kinetic energy of this block when passing through position x = L was equal to...
8:34 | QUESTION 38 - In an experiment conducted in 1843, the Englishman James Prescott Joule showed that it is possible to increase the temperature of water by means of the transfer of mechanical energy. The diagram represents the setup of the apparatus used by Joule in this experiment. The apparatus consisted of a thermally insulated container containing water. Inside this container were paddles connected to weights by a pulley system. When the weights fell due to gravity, the paddles rotated and agitated the water, heating it slightly. A procedure in which the same energy transformation that occurred in Joule's experiment takes place is:
(A) baking a pizza in a wood-fired oven.
(B) warming hands through friction on cold days.
(C) heating ambient air using an air conditioner.
(D) heating water on a gas stove.
(E) moving a car using an internal combustion engine.
11:40 | QUESTION 39 - Objects that behave like lenses have at least one curved face. Some types of lenses, represented below, have been classified into two groups: group 1, which contains thin-edged lenses, and group 2, which contains thick-edged lenses. However, for the object to function as a lens, it is also necessary that the absolute refractive index of the material from which the object is made be different from the absolute refractive index of the medium in which the object is immersed. Thus, comparing these two indices and considering the types of lenses represented in the figures, the absolute refractive index of the object's material should be (A) higher or lower for the lenses of both groups.
(B) exclusively higher for the lenses of both groups.
(C) exclusively lower for the lenses of both groups.
(D) lower only for the lenses of group 1, and higher only for the lenses of group 2.
(E) higher only for the lenses of group 1, and lower only for the lenses of group 2.
15:30 | QUESTION 40 - The figure shows a circuit in which the brightness of lamp L can be controlled by changing the resistance value of a rheostat R v, a device that allows manual adjustment of its resistance value, which alters the electric current in the circuit.
When the value of the rheostat resistance Rv is 60 Ω, the electric current in the circuit is 0.40 A. Assuming the connecting wires are ideal and considering the resistance of the lamp and the potential difference applied to the circuit to be constant, in order for the current in the circuit to become 0.20 A, the value of the rheostat resistance must be:
(A) 90 Ω.
(B) 540 Ω.
(C) 360 Ω.
(D) 30 Ω.
(E) 240 Ω.