Answer:
a. 1.64 m/s²
Explanation:
Centripetal acceleration is the square of tangential velocity divided by the radius.
a = v²/r
First, convert km/h to m/s.
30.0 km/h (1000 m/km) (1 h / 3600 s) = 8.33 m/s
Find the acceleration.
a = (8.33 m/s)² / (42.4 m)
a = 1.64 m/s²
De Broglie's identity gives the relationship between the momentum and the wavelength of a particle:

where
p is the particle momentum
m is its mass
v its velocity
h is the Planck constant

is the wavelength
By re-arranging the equation, we get

and by using the data about the proton, given in the text, we can find the proton's wavelength:
The Tools Used to Measure Density
Scale. Mass is one of the most easily obtained measurements. ...
Graduated Cylinder. The most accurate way to determine an object's volume, especially in the case of an irregularly shaped object, is to immerse it in water and measure the amount of water it displaces. ...
Calculating Density. ...
Hydrometer. ...
The Value of Density.