A rock tumbles straight down from a cliff, it is moving at 20 m/s when it hits. What is the height of the cliff? The mass of the rock is 8 kg. A. 400 m
B. 160 m
C. 2.5 m
D. 20.4 m

1700 j of energy is lost from 0.14 kg object , the temperature decreases from 50°c to 45°c what is the specific heat of this object, amd what is the material ?

Avector a⃗ has a length of 8.6 m and points in the negative x direction. find the x component of the vector −3.7a⃗ .

An electromagnetic wave with frequency 65.0 hz travels in aninsulating magnetic material that has dielectric constant 3.64 andrelative permeability 5.18 at this frequency. the electric fieldhas amplitude 7.20 \times 10^{ - 3} {\rm v}/{\rm m}. a. what is the speed of propagation of the wave? b. what is the wavelength of the wave? c. what is the amplitude of the magnetic field? d. what is the intensity of the wave?