What is the net force on this object?

Find the speed at which Superman (mass=78.0 kg) must fly into a train (mass = 17863 kg) traveling at 75.0 km/hr to stop it. Runn

lapo4ka [179]

Answer with Explanation:

We are given that

Mass of superman=m=78 kg

Mass of train=m'=17863 kg

Speed of train=u'=75 km/h= $75\times \frac{5}{18}=20.8 m/s$

$1 km/h=\frac{5}{18} m/s$

Let initial speed of superman=u

Momentum=mv

Using the formula

$78u=17863\times 75$

$u=\frac{17863\times 75}{78}$

$u=17175.9 km/h$

Average horizontal force=0.58

Deceleration $a=-0.58\times 9.8=-5.68 m/s^2$

Final speed of train=v'=0

$v=u+at$

Using the formula

$0=20.8-5.68t$

$5.68t=20.8$

$t=\frac{v'-u'}{a}=\frac{0-20.8}{-5.68}$

$t=3.66 s$

$v^2-u^2=2as$

Using the formula

$0-(20.8)^2=2(-5.68)a$

$(20.8)^2=2(5.68)s$

$s={\frac{(20.8)^2}{2(5.68)}=38.1 m$

6 0

3 years ago

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A body is thrown vertically upwards, remaining 4s in the air. Calculate the maximum height that the body reaches.

zmey [24]

Answer:

20 m

Explanation:

Given:

v = 0 m/s

a = -10 m/s²

t = 4 s / 2 = 2 s

Find: Δy

Δy = vt − ½ at²

Δy = (0 m/s) (2 s) − ½ (-10 m/s²) (2 s)²

Δy = 20 m

3 0

3 years ago

What happens to a car that experiences an increase in kinetic energy

Allisa [31]

Answer:

Your moving vehicle has kinetic energy; as you increase your vehicle's speed, your vehicle's kinetic energy increases. The greater your vehicle's kinetic energy, the greater the effort that will be required to stop the vehicle.

Explanation:

I hope this explained up above. Have a great dayyyy:)

4 0

3 years ago

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A large, metallic, spherical shell has no net charge. It is supported on an insulating stand and has a small hole at the top. A

tino4ka555 [31]

Answer:

(a) Negative Q

(b) Positive Q

Explanation:

Charge is the inherent property of matter due to the transference of electrons.

There are three methods of charging a body.

(i) Charging by friction: When two uncharged bodies rubbed together, then one body gets positive charged and the other is negatively charges it is due to the transference of electrons form one body to another.

(ii) Conduction: when a charged body comes in contact with the another uncharged body, the uncharged body gets the same charge and the charge is distributed equally.

(iii) Induction: When a uncharged body keep near the charged body, the uncharged body gets the same amount of charge but opposite in sign.

(a) When a small tack of charge Q is lowered into the hole, then due to the process of induction, the charge on the inner surface of the shell is - Q.

(b) Due to the process of conduction, the charge on the outer surface of the shell is Q.

7 0

3 years ago

A uniform hollow spherical ball of mass 1.75 kg and radius 40.0 cm rolls without slipping up a ramp that rises at 30.0° above th

chubhunter [2.5K]

Answer:

The acceleration of the ball's center of mass = 2.94 m/s²

Explanation:

The speed of the ball at the base of the ramp, v = 2.63 m/s

Mass of the ball = 1.75 kg

Radius of the ball, R = 40 cm = 0.4 m

In this motion, potential energy due to the height of the ball is converted to linear angular kinetic energy

Based on the law of energy conservation

Potential energy = Linear KE + angular KE

KE = kinetic Energy

Linear KE = 0.5 mv²

Linear KE = 0.5 * 1.75 * 2.63²

Linear KE = 6.052 J

Angular KE = 0.5 Iω²

I = 2/ 3 MR² = 0.667 * 1.75 * 0.4²

I = 0.187 N.s

ω = V/R = 2.63/0.4

ω = 6.575 Rad/s

Angular KE = 0.5 * 0.187 * 6.575²

Angular KE = 4.04 J

PE = mgh = 1.75 * 9.8 * h = 17.15h

Using the law of energy conservation

17.15h = 6.052 + 4.04

h = 10.092/17.15

h = 0.589 m

$h = Ssin \theta\\S = h/sin \theta\\S = 0.589/sin30\\S = 1.178 m\\$

Using the equation of motion

$v^{2} = u^{2} + 2as\\2.63^{2} = 0^{2} + 2a(1.178)\\6.917 =2.356a\\a = 6.917/2.356\\a =2.94 m/s^{2}$

5 0

4 years ago