Two objects crash into each other. One had a mass of 15 kg and a velocity of -12 m/s. The other had a mass of 5 kg and a velocity of 42 m/s What is the momentum of the system?​

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. you see that the patch of light seems to be a circular diffraction pattern. it appears that the central maximum is about 1 cm across and you estimate that the distance from the window shade to the wall is about 3 m. what is (a) the average wavelength of sunlight? (b) the diameter of the pinhole?

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire

If the force applied to an object remains constant, is more power needed for the object to move faster ? explain