The average speed will be:
Total distance travelled divided by time taken
Total distance (in metres)= 80+125+45=250
Total time (minutes) =10
250/10
=25
Thus Mary's average speed is 25 metres per minute.
Answer:
Explanation:
Distance travelled by Henrietta in 5.5 s = 4.15 x 5.5 = 22.825 m .
Time taken by lunch of bagels to fall vertically by 55.2 m . Let it be t .
s = ut + 1/2 g t²
55.2 = 0 + .5 x 9.8 x t²
t² = 11.26
t = 3.356 s
By the time the lunch of bagels touches the hand of Henrietta , she would have travelled further by distance
s = 3.356 x 4.15 = 13.9 m
She is now at distance of 22.825 + 13.9 = 36.725 m from window .
So lunch of bagels must travel a horizontal distance of 36.725 m in 3.356 s which the time of fall of bagel .
Speed of bagel = distance / time
= 36.725 / 3.356
= 10.94 m /s
b )
Henrietta is 36.725 m from window at the time when she catches the bangel.
Explanation :
When a person is sliding with constant velocity, the forces that are acting on him are :
(1) Weight, W = mg where g is acceleration due to gravity.
(2) Friction forces acting opposite to the direction of motion.
(3) Normal force.
The forces acting on the person is balanced because the person is sliding with constant velocity.
From figure it is clear that, friction force is balanced by 
and normal is balanced by 
.
Answer:
The max speed is 8m/s, 3 seconds at this speed gives 24mts, at 9 seconds has traveled 64mts and at 7,5 52mts
Explanation:
The max speed can be calculated since, at 6 seconds is at 40 mts from the starting point and at constant speed is at 72 mts 10 seconds after the start of the race, then the constant max speed is (72-40)mts /(10-6)seconds=8 m/s.
the distanced travel at this speed is obtained by multipliying by 3 seconds. that is 8m/s*3s=24 mts. the distance at 9 seconds is 40mt of initial 6 plus 24 additional, that is 64mts and at 7,5 is the 40mts initial plus the 13 additional from 8m/s*1,5s = 12mt, that is 52mts.
