All categories

3 years ago

A heavy object is dropped from a vertical height of 8.0 m. What is its speed when it hits the ground?

1 answer:

5 0

What do you know:
d=-8.0mm (starts higher and ends lower so it is negative)
Vi=0m/s (because it was dropped, not thrown)
A=-9.8m/s^2 (gravity)
Vf=???
Use the equation:
Vf^2=Vi^2+2A(d)
Vf^2=2(-9.8)(-8.0)
Vf^2= 156.8 -->find the square root of this
Final answer: Vf= 12.5m/s

You might be interested in

The average intensity of sunlight at the top of the earth's atmosphere in 1390 w/m2. what is the maximum energy that a 34-m x 46

slavikrds [6]

Panel surface area =34m×46m=1,564m^2
total power =1564m^2×1390w/m^2
=2173960watts
now you must calculate total energy.
Energy = power×Time
However time must be in seconds so we multiply 2hrs×60min×60s=7200seconds
7200s×2173960w =15,652,512,000 joules of energy

7 0

3 years ago

A 75.0-kg person is riding in a car moving at 20.0 m/s when the car runs into a bridge abutment. (a) calculate the average force

iragen [17]

(a) $-1.5\cdot 10^6 N$

First of all, we need to calculate the acceleration of the person, by using the following SUVAT equation:

$v^2 -u ^2 = 2ad$

where

v = 0 is the final velocity

u = 20.0 m/s is the initial velocity

a is the acceleration

d = 1.00 cm = 0.01 m is the displacement of the person

Solving for a,

$a=\frac{v^2-u^2}{2d}=\frac{0-20.0^2}{2(0.01)}=-20000 m/s^2$

And the average force on the person is given by

$F=ma$

with m = 75.0 kg being the mass of the person. Substituting,

$F=(75)(-20000)=-1.5\cdot 10^6 N$

where the negative sign means the force is opposite to the direction of motion of the person.

b) $-1.0\cdot 10^5 N$

In this case,

v = 0 is the final velocity

u = 20.0 m/s is the initial velocity

a is the acceleration

d = 15.00 cm = 0.15 m is the displacement of the person with the air bag

So the acceleration is

$a=\frac{v^2-u^2}{2d}=\frac{0-20.0^2}{2(0.15)}=-1333 m/s^2$

So the average force on the person is

$F=ma=(75)(-1333)=-1.0\cdot 10^5 N$

7 0

4 years ago

A particle beam is made up of many protons, each with a kinetic energy of 3.25times 10-15 J. A proton has a mass of 1.673 times

ArbitrLikvidat [17]

Answer:

The magnitude of a uniform electric field that will stop these protons in a distance of 2 m is 1.01 x $10^{-4}$ N/C

Explanation:

given information,

kinetic energy, KE = 3.25 x $10^{-15}$ J

proton's mass, m = 1.673 x $10^{-27}$ kg

charge, q = 1.602 x $10^{-19}$ C

distance, d = 2 m

to find the electric field that will stop the proton, we can use the following equation:

E = F/q

= (KE/d) / q , KE = Fd --> F = KE/d

= KE/qd

= (3.25 x $10^{-15}$ J) / (1.602 x $10^{-19}$ C)(2 m)

= 1.01 x $10^{-4}$ N/C

3 0

3 years ago

What is a magnetic field?

monitta

A magnetic field is charged electricity acting in the forced of magnatism

4 0

3 years ago

At a certain location, the horizontal component of the earth's magnetic field is 2.5 × 10−5 T, due north. A proton moves eastwar

Bogdan [553]

Answer:

v = 4.10 10⁻³ m / s

Explanation:

For this exercise we will use Newton's second law where the force is magnetic

F -W = m a

As the field is directed to the north and the proton to the east, using the rule of the right hand the force is vertical upwards, the force balances the weight the acceleration is zero

F = W

q v B = m g

Let's calculate the speed

v = m g / (q B)

v = 1,673 10⁻²⁷ 9.8 / (1.6 10⁻¹⁹ 2.5 10⁻⁵)

v = 4.10 10⁻³ m / s

7 0

4 years ago