A flea is able to jump straight up about 0.52 m. It has been said that if a flea were as big as a human, it would be able to jump over a 100-story building! When an animal jumps, it converts work done in contracting muscles into gravitational potential energy (with some steps in between). The maximum force exerted by a muscle is proportional to its cross-sectional area, and the work done by the muscle is this force times the length of contraction. If we magnified a flea by a factor of 1040, the cross section of its muscle would increase by 1040² and the length of contraction would increase by 1040. How high would this "super flea" be able to jump? (Don't forget that the mass of the "super flea" increases as well.)

in meters

How does hockey equipment (helmets, neck guard, mouth guard, padding & skates) for injury prevention relate to clinical biomechanics?

A father racing his son has half the kinetic energy of the son, who has two-fifths the mass of the father. The father speeds up by 3.0 m/s and then has the same kinetic energy as the son.

While getting ready for work one morning I encountered something I can't figure out.

I wear glasses and without them objects are blurry unless I get very close, within a few inches. I always take my glasses off when I blow dry my hair in the morning. While standing in front of the mirror in my bathroom I can see a reflection of the tv screen in the bedroom. It is blurry when my glasses are off and much clearer when I put my glasses on. One morning I was interested in a show on tv whilst I was drying my hair so I figured I could watch what was going on if i put my face very close to the mirror while I dried my hair. I tried but no matter how close I got to the mirror the reflected image of the tv stayed blurry. I was close enough to where I normally can see an object clearly without my glasses. I can't figure out why the reflection remained blurry despite my closeness to the mirror. Why would that be?

In your own words describe the rotation of the earth and its revolution around the sun in terms of the Foucault Pendulum experiment and parallax and the aberration of starlight.

Thinking about the 2nd law of Thermodynamics, list 4 examples of irreversible processes and why you know they're irreversible.

The inner workings of most electronic devices for diagnostic imaging are temperature-sensitive, in that they will not function properly if safe operating temperature is exceeded. However, these devices also include internal components that emit considerable heat within the device.

Provide TWO specific strategies that an equipment designer could employ to reduce heating of the temperature-sensitive components in an electronic device,  explain how physics concepts are applied in each strategy.

Heavenly Dog eating the Sun
As an astronomy lover, there is no way for you to miss the partial solar eclipse.
(a) It is not safe to observe the eclipse with your naked eyes. Why?
(b) Unfortunately, you do not have the right solar filter to do the observation. You will project the image onto a piece of paper instead. You expect to see some sunspots on the image. Which scientist discovered sunspots, and what was the implication of the discovery?
(c) Your foreign friend has promised to send you his photos of the total solar eclipse. Why is the total eclipse viewable at his city but not yours?

A uniform, thin, solid door has height 2.30 m, width 0.810 m, and mass 24.5 kg.

(a) Find its moment of inertia for rotation on its hinges.
kg

Early test flights for the space shuttle used a "glider" (mass of 980 kg including pilot). After a horizontal launch at 500 km/h at a height of 4000 m , the glider eventually landed at a speed of 220 km/h .

a) What would its landing speed have been in the absence of air resistance?

b) What was the average force of air resistance exerted on it if it came in at a constant glide angle of 14 ∘ to the Earth's surface?

A ski starts from rest and slides down a 30 ∘ incline 70 m long.

a) If the coefficient of friction is 0.095, what is the ski's speed at the base of the incline?

b) If the snow is level at the foot of the incline and has the same coefficient of friction, how far will the ski travel along the level? Use energy methods.

A proton in a high-energy accelerator moves with a speed of c/2. Use the work–kinetic energy theorem to find the work required to increase its speed to the following speeds.

(a) 0.530c
MeV

(b) 0.940c
GeV

A computer is reading data from a rotating CD-ROM. At a point that is 0.0206 m from the center of the disk, the centripetal acceleration is 174 m/s². What is the centripetal acceleration at a point that is 0.0841 m from the center of the disc?

SCENERIO 1

A solid, homogeneous sphere with a mass of m₀, a radius of r₀ and a density of ρ₀ is placed in a container of water. Initially the sphere floats and the water level is marked on the side of the container. What happens to the water level, when the original sphere is replaced with a new sphere which has different physical parameters? Notation: r means the water level rises in the container, f means falls, s means stays the same. Combination answers like 'f or s' are possible answers in some of the cases.

r, f, s, r or s, f or s  The new sphere has a density of ρ < ρ₀ and a radius of r = r₀.
r, f, s, r or s, f or s  The new sphere has a radius of r = r₀ and a mass of m < m₀.
r ,f ,s ,r or s ,f or s  The new sphere has a radius of r < r₀ and a mass of m = m₀.

SCENERIO 2

A solid, homogeneous sphere with a mass of m₀, a radius of r₀ and a density of ρ₀ is placed in a container of water. Initially the sphere floats and the water level is marked on the side of the container. What happens to the water level, when the original sphere is replaced with a new sphere which has different physical parameters? Notation: r means the water level rises in the container, f means falls, s means stays the same. Combination answers like 'r or f or s' are possible answers in some of the cases.

r, f, s, r or s, f or s, r or f or s  The new sphere has a density of ρ > ρ₀ and a radius of r < r₀.
r, f, s, r or s, f or s, r or f or s  The new sphere has a radius of r < r₀ and a mass of m > m₀.
r, f, s, r or s, f or s, r or f or s  The new sphere has a density of ρ < ρ₀ and a mass of m > m₀.

A uranium-238 nucleus at rest undergoes radioactive decay, splitting into an alpha particle (helium nucleus) with mass 6.64×10-27 kg and a thorium nucleus with mass 3.89×10-25 kg. The measured kinetic energy of the alpha particle is 6.73×10-13 J. If after the decay, the thorium nucleus is observed to move in the negative z direction. After the decay, what direction did the alpha particle move? possible answers: Positive x, Negative x, Positive y, Negative y, Positive z, Negative z. After the decay, what is the kinetic energy of the thorium nucleus?