Answer:
Buoyant force = 3.0 N
The object will not float.
Explanation:
Apparent weight of a body immersed in water is the actual weight of object minus buoyant force
Given in the question that;
Weight of object in air = 7.0 N
Apparent weight of object = 4.0 N
4.0 N = 7.0 N - Buoyant force
Buoyant force = 7.0 - 4.0 = 3.0 N
In this case, the buoyant force is less than weight of the object thus the object will sink.
Answer:
a) -5.40 rad/s
b) -2.842 rad/s²
Explanation:
The direction is important in dealing with such questions. Clockwise is considered negative and counterclockwise is considered positive
a) Δω = final angular velocity - initial angular velocity
= -2.70 rad/s - 2.70 rad/s
= -5.40 rad/s
b) ∝ = Δω/Δt = (-5.40 rad/s)/1.90s = -2.842 rad/s²
Answer:
Part a: When the road is level, the minimum stopping sight distance is 563.36 ft.
Part b: When the road has a maximum grade of 4%, the minimum stopping sight distance is 528.19 ft.
Explanation:
Part a
When Road is Level
The stopping sight distance is given as

Here
- SSD is the stopping sight distance which is to be calculated.
- u is the speed which is given as 60 mi/hr
- t is the perception-reaction time given as 2.5 sec.
- a/g is the ratio of deceleration of the body w.r.t gravitational acceleration, it is estimated as 0.35.
- G is the grade of the road, which is this case is 0 as the road is level
Substituting values

So the minimum stopping sight distance is 563.36 ft.
Part b
When Road has a maximum grade of 4%
The stopping sight distance is given as

Here
- SSD is the stopping sight distance which is to be calculated.
- u is the speed which is given as 60 mi/hr
- t is the perception-reaction time given as 2.5 sec.
- a/g is the ratio of deceleration of the body w.r.t gravitational acceleration, it is estimated as 0.35.
- G is the grade of the road, which is given as 4% now this can be either downgrade or upgrade
For upgrade of 4%, Substituting values

<em>So the minimum stopping sight distance for a road with 4% upgrade is 528.19 ft.</em>
For downgrade of 4%, Substituting values

<em>So the minimum stopping sight distance for a road with 4% downgrade is 607.59 ft.</em>
As the minimum distance is required for the 4% grade road, so the solution is 528.19 ft.
Rolling friction is considerably less than sliding friction as there is no work done against the body that is rolling by the force of friction. For a body to start rolling a small amount of friction is required at the point where it rests on the other surface, else it would slide instead of roll.