The mass of the lawn mower can be calculated from the expression force is equal to the product of mass and acceleration. We do as follows:
F = ma
70 = m(1.8)
m = 38.89 kg
The normal force is the upward force perpendicular with the object. For this case it is equal with Wcos(50). We calculate as follows:
Fn = Wcos50 = 38.89(9.81)(cos50) = 245.23 N
Answer:
a) 2250 J
b) 0 J
c) 2250 J
Explanation:
a) Since, the process is isochoric
the change in internal energy

Here, n = 0.2 moles
Cv = 12.5 J/mole.K
We have to find T_f so we can use gas equation as
![\frac{P_1V_1}{P_2V_2} =\frac{T_i}{T_f}\\Since, V_1=V_2 [isochoric/process]\\\Rightarrow \frac{P_{atm}}{4P_{atm}} = \frac{300}{T_f} \\\Rightarrow T_f = 1200 K](https://tex.z-dn.net/?f=%5Cfrac%7BP_1V_1%7D%7BP_2V_2%7D%20%3D%5Cfrac%7BT_i%7D%7BT_f%7D%5C%5CSince%2C%20V_1%3DV_2%20%20%20%20%5Bisochoric%2Fprocess%5D%5C%5C%5CRightarrow%20%5Cfrac%7BP_%7Batm%7D%7D%7B4P_%7Batm%7D%7D%20%3D%20%5Cfrac%7B300%7D%7BT_f%7D%20%5C%5C%5CRightarrow%20T_f%20%3D%201200%20K)
So, 
b) Since, the process is isochoric no work shall be done.
c) By first law of thermodynamics we have

Since, Q is positive 2250 J of heat will flow into the system.
Answer:
The net torque is 0.0372 N m.
Explanation:
A rotational body with constant angular acceleration satisfies the kinematic equation:
(1)
with ω the final angular velocity, ωo the initial angular velocity, α the constant angular acceleration and Δθ the angular displacement (the revolutions the sphere does). To find the angular acceleration we solve (1) for α:

Because the sphere stops the final angular velocity is zero, it's important all quantities in the SI so 2.40 rev/s = 15.1 rad/s and 18.2 rev = 114.3 rad, then:

The negative sign indicates the sphere is slowing down as we expected.
Now with the angular acceleration we can use Newton's second law:
(2)
with ∑τ the net torque and I the moment of inertia of the sphere, for a sphere that rotates about an axle through its center its moment of inertia is:
With M the mass of the sphere an R its radius, then:

Then (2) is:

Answer:
The density of the fluid is 1100 kg/m³.
Explanation:
Given that,
Height = 5.00 cm
Pressure at top =594 Pa
Pressure at bottom = 1133 Pa
We need to calculate the change in pressure
Using formula of change in pressure

Where,
= Pressure at bottom
= Pressure at top
put the value into the formula


Using formula of pressure for density


Where,
= density
P = pressure
h = height
Put the value in to the formula


Hence, The density of the fluid is 1100 kg/m³.
Answer:
83%
Explanation:
On the surface, the weight is:
W = GMm / R²
where G is the gravitational constant, M is the mass of the Earth, m is the mass of the shuttle, and R is the radius of the Earth.
In orbit, the weight is:
w = GMm / (R+h)²
where h is the height of the shuttle above the surface of the Earth.
The ratio is:
w/W = R² / (R+h)²
w/W = (R / (R+h))²
Given that R = 6.4×10⁶ m and h = 6.3×10⁵ m:
w/W = (6.4×10⁶ / 7.03×10⁶)²
w/W = 0.83
The shuttle in orbit retains 83% of its weight on Earth.