A car, starting from rest, travels 420 m. If the car takes 9.0 s

an apple in a tree has a gravitational potential energy of 175J and a mass of 0.36g . how high from the ground is the apple

Neko [114]

The equation for potential energy is denoted as;

Pe = mgh,

where m = the mass, g = acceleration due to gravity, and h = vertical height of the apple. We are given the units for everything but height, which is also what we are solving for. We can then algebraically rearrange our initial equation to solve for h;

h = (Pe)/(mg)

Plug in your given units, and solve!

Post-check:

h = Pe/mg

h = 175J/(0.36g)(-9.81m/s^2)

h = appr. 49.5 meters

Note: Potential energy is a vector quantity; the displacement of the apple will be a negative number, but the distance itself, a scalar quantity, will be the absolute value of that.

5 0

3 years ago

If a car travels 400m in 20 seconds how fast is it going? 20 m/s

scoundrel [369]

Answer:

20m/s

Explanation:

Speed = distance / time

Speed = 400/20

Speed = 20

5 0

3 years ago

An astronaut on a small planet wishes to measure the local value of g by timing pulses traveling down a wire which has a large o

Alekssandra [29.7K]

Answer:

$0.53m/s^2$

Explanation:

We are given that

Mass of wire=m=3.6 g= $3.6\times 10^{-3} kg$

1 kg=1000 g

Length of wire=l=1.6 m

Mass of object=m'=3 kg

Time,t=60.1 ms= $60.1\times 10^{-3} s$

$1 ms=10^{-3} s$

Speed,v= $\frac{distance}{time}=\frac{1.6}{60.1\times 10^{-3}}=26.62 m/s$

$g=\frac{v^2m}{m'l}$

Using the formula

$g=\frac{(26.62)^2\times 3.6\times 10^{-3}}{3\times 1.6}=0.53m/s^2$

8 0

3 years ago

A 100-W (watt) light bulb has resistance R=143Ω (ohms) when attached to household current, where voltage varies as V=V0sin(2πft)

Phantasy [73]

Complete Question

A 100-W (watt) light bulb has resistance R=143Ω (ohms) when attached to household current, where voltage varies as V=V0sin(2πft), where V0=110 V, f=60 Hz. The power supplied to the bulb is P=V2R J/s (joules per second) and the total energy expended over a time period [0,T] (in seconds) is $U = \int\limits^T_0 {P(t)} \, dt$