Lauren was playing hockey and took a 90 km/hr slap shot at the goal, 10 m away. If the goalie must move her glove 0.50 m to stop the puck, and her reaction time is 0.18 seconds, how fast must she move her glove?
To find out how fast the goalie must move her glove, we can use the concept of velocity.
First, let's convert the distance from meters to kilometers so that the units are consistent. 10 meters is equivalent to 0.01 kilometers.
Now, we can calculate the time it takes for the puck to cover the distance of 10 meters. We can use the formula: time = distance/velocity.
time = 0.01 km / 90 km/hr
To get the time in hours, we divide 0.01 km by 90 km/hr:
time = 0.01/90 = 0.0001111 hours
Since the goalie's reaction time is given in seconds, we need to convert the result to seconds:
0.0001111 hours * (60 minutes/hour) * (60 seconds/minute) = 0.4 seconds (rounded to one decimal place)
So, it takes the puck approximately 0.4 seconds to travel the 10 meters.
Now, we can calculate the speed at which the goalie needs to move her glove to stop the puck.
The total distance the goalie needs to cover is the sum of the puck distance (10 m) and the additional glove distance (0.50 m), which gives us 10 + 0.50 = 10.50 m.
Now, we can use the formula for velocity to find the speed:
velocity = distance / time
velocity = 10.50 m / 0.4 s
velocity = 26.25 m/s (rounded to two decimal places)
Therefore, the goalie must move her glove at a speed of approximately 26.25 m/s to stop the puck.
First convert 90 km/h to 25 m/s. The puck reaches the goal in 10/25 = 0.40 s.
She has 0.22 s to move her glove 0.50 m after her reaction time delay.
0.50/0.22 = ? m/s