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Brut [27]
3 years ago
8

A boy is exerting a force of 70 N at a 50-degree angle on a lawn mower. He is accelerating at 1.8 m/s2. Round the answers to the

nearest whole number.
What is the mass of the lawn mower?

⇒ 25 kg

What is the normal force exerted on the lawn mower?

⇒ 299 N
Physics
1 answer:
LenaWriter [7]3 years ago
4 0

Explanation:

Given that,

Force, F = 70 N

Angle, \theta=50^{\circ}

Acceleration of the boy, a = 1.8 m/s²

(a) Net force is equal to the product of mass and acceleration. So,

m=\dfrac{F}{a}\\\\m=\dfrac{70}{1.8}\\\\m=38.89\ kg

(2) Normal force = upward force

So,

F=mg\cos\theta\\\\F=38.89\times 9.81\times \cos(50)\\F=245.23\ N

Hence, mass is 38.89 kg and the normal force is 245.23 N.

You might be interested in
Change in Energy Quick Check
nika2105 [10]

Answer:

The force of gravity on the object decreases.  (FALSE)

The potential energy of the object decreases.  (TRUE)

The acceleration due to gravity decreases.  (FALSE)

The kinetic energy of the object decrease (FALSE)

Explanation:

<u>FORCE OF GRAVITY:</u>

Force of gravity on the object is the weight of object, which depends upon the mass and value of acceleration due to gravity (W = mg). Since, the value mass is constant on Earth and acceleration due to gravity is also constant on earth.

Therefore, force of gravity remains same on the object. <u>The statement is false.</u>

<u></u>

<u>POTENTIAL ENERGY:</u>

Potential energy of object depends upon the mass, value of acceleration due to gravity, and change in height of object (P.E = mgΔh). Since, the value mass is constant on Earth and acceleration due to gravity increases as the object moves towards the surface of earth. But, the height of object is decreasing.

Therefore, potential energy of object decreases. <u>The statement is true.</u>

<u></u>

<u>ACCELERATION DUE TO GRAVITY:</u>

Acceleration due to gravity depends upon the altitude (gh = g[1 - 2h/Re]). Since, the height of object is decreasing.

Therefore, acceleration due to gravity increases. <u>The statement is false.</u>

But, this change is not significant.

<u>KINETIC ENERGY:</u>

Kinetic Energy of object, which depends upon the mass and velocity of the object (K.E = mv²/2). Since, the value mass is constant on Earth and velocity increases as the object moves towards the surface of earth.

Therefore, kinetic energy of the object also increases. <u>The statement is false.</u>

4 0
3 years ago
The low-frequency speaker of a stereo set has a surface area of 0.06 m2 and produces 2.03 W of acoustical power. What is the int
zimovet [89]

Answer:

33.83W/m²

Explanation:

The intensity of the speake at the surface is

I = P/A

I = 2.03W / 0.06m²

I = 33.83W/m²

8 0
3 years ago
How much heat is absorbed by a 71g iron skillet when its temperature rises from 11oC to 29oC?
diamong [38]
The right formula to use for this calculation is the heat capacity formula, 
Heat absorbed, Q = MCT, Where 
M = Mass of the substance = 71
C = Specific heat capacity for iron = 0.450 J/gc
T = Change in temperature = 29 - 11 = 18
Q = 71 * 0.450 *18 = 575.10
The amount of heat absorbed by the iron skillet is 575 J.
5 0
3 years ago
A 4 kg bowling bowl is sitting on a table 1 meter off the ground. How much potential energy does it have?
il63 [147K]

Answer:

\huge\boxed{\sf P.E. = 39.2\ Joules}

Explanation:

<u>Given Data:</u>

Mass = m = 4 kg

Acceleration due to gravity = g = 9.8 m/s²

Height = h = 1 m

<u>Required:</u>

Potential Energy = P.E. = ?

<u>Formula:</u>

P.E. = mgh

<u>Solution:</u>

P.E. = (4)(9.8)(1)

P.E. = 39.2 Joules

\rule[225]{225}{2}

Hope this helped!

<h3>~AH1807</h3>
5 0
3 years ago
The length of a simple pendulum is 0.66 m, the pendulum bob has a mass of 310 grams, and it is released at an angle of 12 degree
lina2011 [118]
A) the periodic time is given by the equation;
 T= 2π√(L/g)
For the frequency will be obtained by 1/T (Hz)
T = 2 × 3.14 √ (0.66/9.81)
   = 6.28 × √0.0673
    = 1.6289 Seconds
Frequency = 1/T = f = 1/1.6289
 thus; frequency = 0.614 Hz

b)  The vertical distance, the height is given by
 h= 0.66 cos 12
 h = 0.65 m
Vertical fall at the lowest point = 0.66 - 0.65 = 0.01 m
Applying conservation of energy
energy lost (MgΔh) = KE gained (1/2mv²)
 mgh = 1/2mv²
  v² = 2gΔh = 2×9.81 × 0.01 
                   = 0.1962
v = 0.443 m/s

c) total energy = KE + GPE = KE when GPE is equal to zero (at the lowest point possible)
Thus total energy is equal to;
E = 1/2mv²
   = 1/2 × 0.310 × 0.443²
   = 0.0304 J


4 0
3 years ago
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