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Physics
Of a stone of mass 48g is released from a catapult whose rubber stress is 12mm assuming the first constant of the rubber 200nm-1 determine the velocity with which the stone leave the catapult
How does the theory of inflation explain the observed fact that our universe has a geometry that is close to being flat?
Select one answer?
1)Because curved regions of space-time have a larger effective density of false vacuum and hence will expand more rapidly.
2)Because the universe can only roll off the top of the mexican hat and hence stop inflation if its geometry is locally flat.
3)Because strongly curved regions will not last long enough for life to evolve
4)Because any smooth curved shape, if enlarged enough, will look flat locally.
5)Because if space was curved, regions of space with different laws of physics would collide, which is not observed.
Select one answer?
1)Because curved regions of space-time have a larger effective density of false vacuum and hence will expand more rapidly.
2)Because the universe can only roll off the top of the mexican hat and hence stop inflation if its geometry is locally flat.
3)Because strongly curved regions will not last long enough for life to evolve
4)Because any smooth curved shape, if enlarged enough, will look flat locally.
5)Because if space was curved, regions of space with different laws of physics would collide, which is not observed.
The steam is heated to raise its temperature to 150°C. Show the process on a sketch of the p–v diagram, and evaluate the pressure, increase in enthalpy, increase in internal energy, increase in entropy of steam, and the heat transfer. Evaluate also the pressure at which the steam becomes dry saturated.
Physics
Solve the problems below and show the complete solution.
2. Strong winds can apply a significant enough force to tall skyscrapers to set them into a back-and-forth
motion. The A of these motions is greater at the higher floors and barely observable for the lower floors.
It is said that one can even observe the vibrational motion of the Sears Tower in Chicago on a windy day.
As the Sears Tower vibrates back and forth, it makes about 8.6 vibrations in 60sec. Determine the
frequency and the period of vibration.
2. Strong winds can apply a significant enough force to tall skyscrapers to set them into a back-and-forth
motion. The A of these motions is greater at the higher floors and barely observable for the lower floors.
It is said that one can even observe the vibrational motion of the Sears Tower in Chicago on a windy day.
As the Sears Tower vibrates back and forth, it makes about 8.6 vibrations in 60sec. Determine the
frequency and the period of vibration.
Physics
Solve the problems below and show the complete solution.
1. Students are doing the Period of a Pendulum Lab. They observe that a pendulum makes exactly 10 complete back and forth cycles of motion in 31.8sec. Determine the period of the pendulum.
Physics
A 5 kg present is initially at rest on the floor: μ = 0.25. A force of 120 N is then exerted onto the present, directed at an angle of 30∘ above the horizontal. The applied force is exerted onto the present for 3.0 s, at which point the applied force is removed. The present then moves as a projectile. It lands on the floor without bouncing and then slides to a stop. How far does the present end up from where it started?
Physics
A 5 kg present is initially at rest on the floor: μ = 0.25. A force of 120 N is then exerted onto the present, directed at an angle of 30∘ above the horizontal. The applied force is exerted onto the present for 3.0 s, at which point the applied force is removed. The present then moves as a projectile. It lands on the floor without bouncing and then slides to a stop. How far does the present end up from where it started?
Franz is standing on a hill throwing a snowball at a target, as illustrated in the diagram
below. The centre of the target is located 2.0 m below his hand.
Franz tosses the snowball with a velocity of 4.2 m/s at an angle of 50° above the
horizontal. The snowball hits the centre of the target, much to Franz’s delight. What is the horizontal distance between Franz and the target?
below. The centre of the target is located 2.0 m below his hand.
Franz tosses the snowball with a velocity of 4.2 m/s at an angle of 50° above the
horizontal. The snowball hits the centre of the target, much to Franz’s delight. What is the horizontal distance between Franz and the target?
Physics
A leopard is sleeping on a branch in a tree. While asleep, the leopard rolls off her branch
and falls from rest, hitting the ground 1.1 s later. How high is the branch from the ground?
and falls from rest, hitting the ground 1.1 s later. How high is the branch from the ground?
Physics
Gear, one of a set of toothed wheels that work together to alter the relation between the speeds of a driving mechanism had been widely used nowadays especially in transportation industry such as car, ship and aircraft. By providing diagrams / figures, explain FOUR (4) types of gears.
(10 marks)
(10 marks)
