<u>Answer:</u>
Velocity of the dog relative to the road = 26.04 m/s 3.15⁰ north of east.
<u>Explanation:</u>
Let the east point towards positive X-axis and north point towards positive Y-axis.
Speed of truck = 25 m/s north = 25 j m/s
Speed of dog = 1.75 m/s at an angle of 35.0° east of north = (1.75 cos 35 i + 1.75 sin 35 j)m/s
= (1.43 i + 1.00 j) m/s
Velocity of the dog relative to the road = 25 j + 1.43 i + 1.00 j = 1.43 i + 26.00 j
Magnitude of velocity = 26.04 m/s
Angle from positive horizontal axis = 86.85⁰
So Velocity of the dog relative to the road = 26.04 m/s 86.85⁰ east of north = 26.04 m/s 3.15⁰ north of east.
(B) 2.25cm
<u>Explanation:</u>
Given:
At 40 hours, the height of the bamboo plant is 2.1cm
At 50 hours, the height of the bamboo plant is 2.4cm
Height of the bamboo plant after 45 hours = ?
The difference in length from 40 to 50 hours = 2.4 - 2.1cm
= 0.3 cm
Mean of 40 and 50 is 45.
Thus,
At 45 hours, the height will increase by 0.3/2
= 0.15 cm
Height at 45 hour = 2.1 + 0.15cm
= 2.25cm
Therefore, the height of the plant after 45 hours is 2.25cm