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ad-work [718]
3 years ago
14

11. A student lifts a 25 kg mass a vertical distance of 1.6 m in a time of 2.0 seconds.

Physics
1 answer:
goldenfox [79]3 years ago
4 0

Answer:

a) 245 N

b) 392 J

c) 196 W

Explanation:

a) Force needed to lift the 25 kg object is the same as the weight of the object:

Force= m * g = 25kg * 9.8 \frac{m}{s^2} = 245 N

b) Work is the force exerted times the distance moved:

Work = F * d = 245N * 1.6 m = 392 Joules = 392 J

c) The power exerted is the quotient of the work done over the amount of time it took to move the object:

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What is the effect on the force of gravity between two objects if the mass of one object remains unchanged while the distance to
Vadim26 [7]

Answer:

The correct answer to the question is

B. It always decreases

Explanation:

To solve the question, we note that the foce of gravity is given by

F_G=\frac{Gm_1m_2}{r^2} where

G= Gravitational constant

m₁ = mass of first object

m₂ = mass of second object

r = the distance between both objects

If the mass of one object remains unchanged while the distance to the second object and the second object’s mass are both doubled, we have

F_{G2} =\frac{Gm_1(2m_2)}{(2r)^2} = \frac{2}{4} \frac{Gm_1m_2}{r^2}

Therefore the gravitational force is halved. That is it will always decrease

4 0
3 years ago
A bike rider approaches a hill with a speed of 8.5 m/s. The total mass of the bike rider is 91kg. What is the kinetic energy of
Anestetic [448]

a) The kinetic energy (KE) of an object is expressed as the product of half of the mass (m) of the object and the square of its velocity (v²):

KE = \frac{1}{2}m* v^{2}

It is given:

v = 8.5 m/s

m = 91 kg

So:

KE= \frac{1}{2}*91*8.5^{2} =3,287.4J


b) We can calculate height by using the formula for potential energy (PE):
PE = m*g*h

In this case, h is eight, and PE is the same as KE:
PE = KE = 3,287.4 J

m = 91 kg

g = 9.81 m/s² - gravitational acceleration

h = ? - height


Now, let's replace those:

3,287.4= 91 * 9.81 * h

⇒ h = 3,287.4/(91*9.81) = 3,287.4/892.7 = 3.7 m

3 0
3 years ago
The movement of air around an anticyclone is:
N76 [4]
Pretty sure it is clockwise if I am not mistaken
5 0
3 years ago
Read 2 more answers
A particle moves along a straight line. Its position at any instant is given by x = 32t− 38t^3/3 where x is in metre and t in se
Rudik [331]

Answer:

The acceleration of the object is -69.78 m/s²

Explanation:

Given;

postion of the particle:

x = 32t - 38\frac{t^3}{3} \\\\

The velocity of the particle is calculated as the change in the position of the  particle with time;

v = \frac{dx}{dt} = 32 - 38t^2\\\\when \ the \ particle \ is \ at \ rest, \ v = 0\\\\32-38t^2 = 0\\\\38t^2 = 32\\\\t^2 = \frac{32}{38} \\\\t = \sqrt{\frac{32}{38} } \\\\t = 0.918 \ s

Acceleration is the change in velocity with time;

a = \frac{dv}{dt} = -76t\\\\recall , \ t = 0.918 \ s\\\\a = -76(0.918)\\\\a = -69.78 \ m/s^2

4 0
2 years ago
A charged particle moves through a magnetic field. In which situation is the magnetic force zero?
maksim [4K]

Answer:

The answer is the option a.

Explanation:

We know that magnetic force (Fm) is defined as

Fm = q (v x B)

Where q is a the value of the charge, v is the velocity of the charge and B is the value of the magnetic field.

"v x B" is defined as the cross product between the vectors velocity and magnetic field, and if the angle between them is thetha < 180°, then, the cross product is

v x B = vBsin (thetha)

So,

Fm = qvBsin (thetha)

And, in case in which v and B are parallel vectors, thetha is zero, and,

sin (thetha)=sin (0) = 0

So, Fm=0

7 0
3 years ago
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