Physics calculation question (1 Viewer)

[sciencenerd]

Bored at the beach, a physics student resorts to counting water waves. He sits on a pier and
count the water waves washing by their feet. There are 30 full waves passing his feet every
minute. Looking along the pier which is 9.0 m long, he can see 4 wave crests at a time along
the side of the pier. Realizing that these 4 wave crests represent three (3) water wavelengths,
he quickly calculates the speed of the water waves to be:
A. 0.5 ms-1

B. 2.5 ms-1

C. 3.0 ms-1

B. 6.0 ms-1

I got 1.5 ms-1 which unfortunately wasn't one of the options

thank you!!

 

[sciencenerd]

SORRY!
this too.
in particular (d) , since i keep getting an impulse in the opposite direction

A police officer travelling East at 126 kmhr-1
in a 1000 kg police car is following close
behind a (1300 kg + 200 kg vase) delivery truck, which is also travelling East. Suddenly
the delivery truck stops and the police wagon crashes into the delivery truck.

(a) Calculate the momentum of the police car before collision.
(b) If the two vehicles stick together, calculate the total momentum of the wreckage (police-car
+ delivery truck + vase) just after collision.

(c) If the two vehicles stick together, calculate the velocity of the wreckage (police-car +
delivery truck + vase) after collision.


(d) Calculate the impulse of the police car on the delivery truck.

 

[Fizzy_Cyst]

I also get 1.5ms-1!