Albert Jackobs
New member
To make a clay vase, an artist uses a potter's wheel hat has a diameter of 13in. and spins at 120rpm. Find the approximate distance traveled in 1min by a point on the outer edge of the wheel.
distance traveled in 1min by a point on the outer edge of the wheel
=phi * 13 * 120
= 4902.85 in
A ship is approaching a lighthouse known to be 20m high. The apparent size of the lighthouse is 0.005 radians. Ten minutes later the lighthouse has an apparent size of 0.010 radians. What is the approximate speed of the ship (in km/h)?
tan 0.005 = 20 / d1
d1 = 4000 m
tan 0.01 = 20 / d2
d2 = 2000 m
speed
= [ d1 - d2 ] / 0.16666
= 2000 / 0.16666
= 12000 m/hr
= 12 km/hr
are these right?
distance traveled in 1min by a point on the outer edge of the wheel
=phi * 13 * 120
= 4902.85 in
A ship is approaching a lighthouse known to be 20m high. The apparent size of the lighthouse is 0.005 radians. Ten minutes later the lighthouse has an apparent size of 0.010 radians. What is the approximate speed of the ship (in km/h)?
tan 0.005 = 20 / d1
d1 = 4000 m
tan 0.01 = 20 / d2
d2 = 2000 m
speed
= [ d1 - d2 ] / 0.16666
= 2000 / 0.16666
= 12000 m/hr
= 12 km/hr
are these right?