A roller coaster has 800,000 Joules of kinetic energy and is moving with a speed of 40 m's What is the mass of the roller coaster ing?
As boe in the number for your answer, not the units
The formula for kinetic energy is
The formula for potential energy is
velocidorspeed inms
8 - 10m this really 9.8 m son earth but we will use 10 for simplicity

Initial velocity,  u = 4.9 m/sfinal velocity = v m/sinitial height,  h₁ =  245 m    final height, h₂ = 0a = -9.8  m/s²time taken = t secondss = ut + 0.5at²⇒  (h₂-h₁) = ut + 0.5at²⇒  0-245 = 4.9t + 0.5×(-9.8)×t²⇒ -245 = 4.9t - 4.9t²⇒ 4.9t² -4.9t -245 =0solving it, we get   t = 7.59sv  = u +  at = 4.9 -9.8×7.59 = 4.9 - 74.38 = -69.48 m/svelocity is  69.48 m/s downward

Ithink it's  c. i'm sure 

Each student aligns the edge of the object with the left edge of the ruler as shown above. all four students read the ruler with a measurement of 4.6 cm. which statement describes the data they collect? i believe the answer is: the data have poor precision and poor accuracy because of a systematic error.

Answer is  true.  because the sensory memory it can also have a fraction of a second before the information is lost. hope it .