A phone is knocked off a table 800cm of the ground. If the phone is 650g a) what is the gravational potential of the phone? b)what speed will the phone hit the floor at? c)How long will it take for the phone to hit the floor?
UNITS - SI UNITS: 800cm --> 0.8m 0.65kg
a) Ep= mg(change) height
Ep=0.65kg * 9.81m/s2 * 0.80m
Ep=5.10 Joules (J)
b) Gravational Potential = Kinetic energy
Ek = 1/2 mv2
v=Sqrt(Ep/0.5m)
v=sqrt(5.10/0.5*0.65)
v=3.96m/s
c) v=u+ at
t=(v-u)/a
v=3.96m/s u=0m.s a=9.81m/s2
t=3.96/9.81
t=0.40s
JJ
Related Physics A Level answers
All answers ▸What is escape velocity?
How do you use a Variable Resistor to determine values to show the relationship between I and V?
On the line of centres between the Earth and the Moon, there is a point where the net gravitational force is zero. Given that the distance between the two is 385,000 km, and that the Earth has a mass 81x that of the Moon, how far is this point from Earth?
Ignoring air resistance, use an energy argument to find the speed of a ball when it hits the ground if it is dropped from 50m, where m is the mass of the ball.