Answer:
36.87 km/h
Explanation:
Convert all the units in SI system
1 mile = 1609.34 m
d1 = 6 mi = 9656.04 m
t1 = 15 min = 15 x 60 = 900 s
d2 = 3 mi = 4828.02 m
t2 = 10 min = 10 x 60 = 600 s
d3 = 1 mi = 1609.34 m
t3 = 2 min = 2 x 60 = 120 s
d4 = 0.5 mi = 804.67 m
t4 = 0.5 min = 0.5 x 60 = 30 s
Total distance, d = d1 + d2 + d3 + d4
d = 9656.04 + 4828.02 + 1609.34 + 804.67 = 16898.07 m = 16.898 km
total time, t = t1 + t2 + t3 + t4
t = 900 + 600 + 120 + 30 = 1650 s = 0.4583 h
The ratio of the total distance covered to the total time taken is called average speed.
Average speed = 16.898 / 0.4583 = 36.87 km/h
Answer: a) 19.21m b) 3.92secs
Explanation:
a) Maximum height reached by the object is the height reached by an object before falling freely under gravity.
Maximum height = U²/2g
U is the initial velocity = 19.6m/s
g is acceleration due to gravity = 10m/s²
Maximum Height = 19.6²/2(10)
H = 19.21m
b) The time elapsed before the stone hits the ground is the time of flight T= 2U/g
T= 2(19.6)/10
T = 39.2/10
Time elapsed is 3.92secs
Answer:
Change in mechanical energy = work done by friction
so it is equal to
Explanation:
As we know that change in mechanical energy must be equal to the work done by non conservative forces only
So here when block moves down the inclined plane then the work done by friction force is given as
here we have
here we know that
so we have
Now the friction force on the block is given as
now work done by the friction is given as
Answer:
- A book lying on a table - Balanced force
- An airplane cruising in level flight - Balanced
- A rock falling from a cliff - Unbalanced force
- A bridge collapsing in an earthquake - Unbalanced force
- A man sitting on a park bench - Balanced force
- A space shuttle taking off - Unbalanced force
- A car maintaining a constant speed on a straight road - Balanced force
- An airplane landing - Unbalanced force
Explanation:
Usually, one or more forces act on a body at an instant of time. When these forces acting on a body and bring the body in the equilibrium position, the force is said to be balanced. The unbalanced force changes the equilibrium state of the body.
As in the case of an airplane cruising in a level flight, the weight of the plane will be equal to the lift force and the thrust is equal to the drag. So the plane is experiencing a balanced force.
Through an earth-based telescope you can see Jupiter more clearly than Mars because Jupiter is much larger than Mars and through the telescope you see the larger objects more clearly.
