Answer:
c. Equal to the magnitude of the average velocity for the same time period if the direction of motion does not change.
Explanation:
Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.
Mathematically, speed is given by the equation;
Motion can be defined as a change in the location (position) of a physical object or body with respect to a reference point.
This ultimately implies that, motion would occur as a result of a change in location (position) of an object with respect to a reference point or frame of reference i.e where it was standing before the effect of an external force.
The average speed of an object during a specified period of time is equal to the magnitude of the average velocity traveled or covered in the same time period and in a straight line i.e if the direction of motion does not change.
Answer:
Explanation:
Frictional force acting on the child = μ mg cosθ
, μ is coefficient of kinetic friction , m is mass of child θ is inclination
work done by frictional force
μ mg cosθ x d , d is displacement on inclined plane
work done = .13 x 276 x cos34 x 5.9
= 175.5 J
This work will be converted into heat energy.
b ) Initial energy of child = mgh + 1/2 m v ² , h is height , v is initial velocity
= 276 x 5.9 sin34 + 1/2 x 276 / 9.8 x .518² [ mass m = 276 / g ]
= 910.59 + 3.77
= 914.36 J
loss of energy due to friction = 175.5
Net energy at the bottom
= 738.86 J
If v be the velocity at the bottom
1/2 m v² = 738 .86
.5 x (276 / 9.8) x v² = 738.86
v² = 52.47
v = 7.24 m /s .
Answer:
Final angular speed equals 3 revolutions per second
Explanation:
We shall use conservation of angular momentum principle to solve this problem since the angular momentum of the system is conserved
After the disc and the dropped rod form a single assembly we have the final angular momentum of the system as follows
Equating initial and final angular momentum we have
Solving for we get
Thus no of revolutions in 1 second are 6π/2π
No of revolutions are 3 revolutions per second
28 is balanced and unbalanced
Answer:
11.27 m /s
2.98 m / s.
Explanation:
80 km / h = 22.22 m /s
Tanq = 4 / 100
Sinq = .0399
Deceleration acting on inclined plane = g sinq
= 9.8 x .0399
= .3910
Initial speed u = 22.22 m/s
acceleration = - .3910 ms⁻²
v = u - a t
= 22.22 - .3910 x 28
= 22.22 - 10.95
= 11.27 m /s
b ) v² = u² - 2 a s
v² = ( 22.22) ² - 2 x .3910 x 620
= 493.7284 - 484.84
= 8.8884
v = 2.98 m / s.