Well it depends it has to be some kind of metal material if not then it will not pick it up Hope this helps:)
Answer:
(c) 10m/s
Explanation:
to find the speed of the waves you can use the following formula:

λ: wavelength of the wave
T: period
the wavelength is the distance between crests = 48m
the period is the time of a complete oscillation of the wave. In this case you have that the float takes 2.4 s to go from its highest to the lowest point. The period will be twice that time:
T = 2(2.4s)=4.8s
by replacing you obtain:

the answer is (c) 10m/s
Answer:
0.45 m/s in the negative x-direction
Explanation:
From the law of conservation of momentum, the sum of initial momentum equals the sum of final momentum
Momentum, p=mv where m is the mass and v is the velocity
where
is the common velocity,
and
are velocities of magnet moving in positive x-direction and magnet moving in negative x-direction respectively,
and
are masses of magnet moving in positive x-direction and magnet moving in negative x-direction respectively.
Substituting 125 g for
and 85 g for
, 7.33 m/s
, -11.9 m/s for
then



Therefore, the velocity of single unit is 0.45 m/s in the negative x-direction