Answer:
M = 328.70g
Explanation:
From the given values:
V = 346 cm³
M of 1 cm³ of Polythene = 0.95g or 95/100g
Solve:
M = <u>(95×346)</u>
10
= <u>3</u><u>2</u><u>8</u><u>7</u><u>0</u>
100
M = 328.70g
Question:
A 63.0 kg sprinter starts a race with an acceleration of 4.20m/s square. What is the net external force on him? If the sprinter from the previous problem accelerates at that rate for 20m, and then maintains that velocity for the remainder for the 100-m dash, what will be his time for the race?
Answer:
Time for the race will be t = 9.26 s
Explanation:
Given data:
As the sprinter starts the race so initial velocity = v₁ = 0
Distance = s₁ = 20 m
Acceleration = a = 4.20 ms⁻²
Distance = s₂ = 100 m
We first need to find the final velocity (v₂) of sprinter at the end of the first 20 meters.
Using 3rd equation of motion
(v₂)² - (v₁)² = 2as₁ = 2(4.2)(20)
v₂ = 12.96 ms⁻¹
Time for 20 m distance = t₁ = (v₂ - v ₁)/a
t₁ = 12.96/4.2 = 3.09 s
He ran the rest of the race at this velocity (12.96 m/s). Since has had already covered 20 meters, he has to cover 80 meters more to complete the 100 meter dash. So the time required to cover the 80 meters will be
Time for 100 m distance = t₂ = s₂/v₂
t₂ = 80/12.96 = 6.17 s
Total time = T = t₁ + t₂ = 3.09 + 6.17 = 9.26 s
T = 9.26 s
Answer:
Explanation:
a rigid object in uniform rotation about a fixed axis does not satisfy both the condition of equilibrium .
First condition of equilibrium is that net force on the body should be zero.
or F net = 0
A body under uniform rotation is experiencing a centripetal force all the time so F net ≠ 0
So first condition of equilibrium is not satisfied.
Second condition is that , net torque acting on the body must be zero.
In case of a rigid object in uniform rotation , centripetal force is applied towards the centre ie towards the line joining the body under rotation with the axis .
F is along r
torque = r x F
= r F sinθ
θ = 0 degree
torque = 0
Hence 2nd condition is fulfilled.
Answer:
The Density of the block is 4.667g/mL
Explanation:
Given the following data;
Mass of block = 700g
Volume of block = 150cm³
Density = ?
Density can be defined as mass all over the volume of an object.
Simply stated, density is mass per unit volume of an object.
Mathematically, density is given by the equation;
Substituting into the equation, we have;
<em>Density = 4.667g/mL</em>
Explanation:
Below is an attachment containing the solution.
