A toy car runs off the edge of a horizontal table that is 1.21 m high. The car lands 1.39 m away from the edge of the table
How fast was the car moving across the table just before it fell?
____m/s
MY WORK:
h=1/2gt^2 1.21=1/2(9.8)t^2 1.21=4.9t^2 scuare root; .246
but that still isn't the answer! what do i do?
To find the speed of the car just before it fell off the edge of the table, you need to use the principle of conservation of energy.
When the car is still on the table, it has gravitational potential energy, given by the formula:
PE = mgh
Where PE is the potential energy, m is the mass of the car, g is the acceleration due to gravity (approximately 9.8 m/s^2), and h is the height of the table.
When the car falls off the table, all of its gravitational potential energy is converted into kinetic energy as it moves horizontally. The kinetic energy of the car can be calculated using the formula:
KE = 1/2 mv^2
Where KE is the kinetic energy and v is the velocity or speed of the car.
Since energy is conserved, we can equate the potential energy and kinetic energy:
mgh = 1/2 mv^2
The mass of the car cancels out, and you are left with:
gh = 1/2 v^2
Now you can solve for v:
v = sqrt(2gh)
Plugging in the values for g (9.8 m/s^2) and h (1.21 m), you can calculate the speed of the car:
v = sqrt(2 * 9.8 * 1.21) ≈ 4.2 m/s
Therefore, the car was moving at approximately 4.2 m/s across the table just before it fell.