Frequency= speed/ wavelength
f= 3.0 × 10^8 m/s/ <span>3.5 × 10^-9 m
=8.57x10^16
The answer is letter </span><span>B. 8.57 × 10^16 Hz.</span>
The formula for a kinetic energy KE of a falling body is
KE = mgh
where m = mass, g = acceleration due to gravity (9.8 m/s^2, constant), h = height.
The total mass of a skateboader and a skateboard is 64 + 2.0 = 66 kg.
Finally,
KE = 66*9.8*5.0 = 32340 J
The material that is the best choice for the head of a hammer is a metal. Having a metal for a hammer head allows you to have a light-weight but heavy duty hammer. Since a hammer is a tool that is used to strike an object repeatedly, a light weight is essential since you would be repeatedly making that motion.