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Physics
Jane is initially walking at a certain speed so that her kinetic energy is 150 J. Then the rain starts to fall and Jane runs at a rate of 4.2m/s. She has a mass of 50.0kg.
a) what is her initial speed before the rain starts?
b) find the change in Jane's kinetic energy when she starts running?
a) what is her initial speed before the rain starts?
b) find the change in Jane's kinetic energy when she starts running?
(i) Describe the Einstein theory of photo electric effect and draw the circuit diagram of the
apparatus to find Plank’s constant by Photo electric effect.
Physics
Suppose that the breakfast of a typical 65kg adult gives him 1.85x10^5 J of energy. How long does he have to do push-ups to burn at least 50 percent of this energy?
Physics
A force of 35 N is needed to keep a 5.0 kg body moving at a constant speed of 7.5 m/s. What power is needed to sustain the motion of the mass?
Physics
The Sun generates energy because of nuclear reactions that occur in its core. A sequence of reactions that do this is called the PP I chain (pronounced “p p one chain”). In the PP I chain, four protons fuse into a helium-4 nucleus and two positrons, since charge is conserved. Also emitted are two neutrinos, since angular momentum is conserved. The neutrinos have no charge and negligible mass. Assume all motion in the PP I chain is non-relativistic, except for the neutrinos. How many MeV of energy does one PP I chain generate? Include the energy generated by the positrons annihilating with electrons that must already be in the Sun, since the Sun is electrically neutral.
Physics
A liquid-in-glass thermometer is replaced by a similar thermometer with a larger bulb. No other change is made.
State and explain the effect on the sensitivity.
Physics
A 2000 kg car is accelerated uniformly from rest to a speed of 15 m/s in 10 s. What is the magnitude of the unbalanced force acting on the car?
Physics
A 740kg elevator accelerates upward at 1.1m/s2, pulled by a cable of negligible mass. Find the tension force in the cable.
Physics
A shopper pushes her 25 kg grocery cart by a force of 225 N inclined at an angle of 60° with the horizontal through a distance of 7.5 m. Find the work done by the force applied by the shopper.
A 50.0 N force is applied at an angle of 30.0 degrees north of east to a 5.78 kg box. Assuming there is a coefficient of kinetic friction of 0.389 between the table and the box, what is the time it takes to travel 3.00 meters?
