What is the sum of 1123 and 10.3 written by scientific notation with the correct number of significant figures

Please can you help me with questions 3 and 4?

Bill and Amy want to ride their bikes from their neighborhood to school which is 21.3 kilometers away. It takes Amy 38 minutes to arrive at school. Bill arrives 23 minutes after Amy. (Add Amy's time with 23 min to get Bill's time.) How much faster (in meters/second) is Amy’s average speed for the entire trip?  m/s (Convert km to m and min to sec)

The equation for the motion of an object with constant acceleration is d= do + vt + at, where d is distance from a given point in meters, do is the initial distance from the starting point in meters, v is the starting velocity in meters per second, a is acceleration in meters per second squared, and t is time in seconds. A car is stopped at a traffic light. When the light turns green, the driver begins to drive, accelerating at a constant rate of 4 meters squared. A bus is traveling at a speed of 15 meters per second in another lane. The bus is 7 meters behind the car as it begins to accelerate. per second Find when the bus passes the car, when the car passes the bus, and how far each has traveled each time they pass one another. it lad wod

The velocity - time graph of the journey of a person is shown in the attached graph. How much distance, in meters, did the person cover during the whole journey, from time = 0 to time = 50 seconds? Round your answer to the nearest integer. Speed (m/s) 25 20 15 10 5 0 0 10 20 Time (s) 30 40 50

The distance travelled of a car is given by the values in the following table.Fill in the blanks to answer this question Time t (seconds) 1 4 Distance s (feet) 16 35 71 112 179 Find the car's average velocity for the following time intervals: Time interval [1,3] feet/ second Time interval [2,3] feet/second

4) A freight train left Vancouver at 1:00pm and traveled 100 km east. The train arrived at the final destination at 3:00pm. What was the train's velocity? 5) A bus took 3 hrs to drive from Dufur, Oregon to Portland, Oregon. The bus traveled at 80km/hr. How many kilometers was the trip? to reach your 6) If you drive a distance of 100 km at 25 km/hr, how long will it take destination? you 7) If you drive a distance of 100km at 50 km/hr, how long will it take you to reach your destination? 8) If you walk 12 km in 4 hours, how fast are you walking? nt wos his speed? Should H

How many significant figures does each of the following numbers have?a. 6.21                 b. 62.1c. 0.620               d. 0.062

22. A tennis ball travels down a ramp onto a table and at the end of the ramp has a velocity of .75 m/s. The ball is released from rest at the top of the ramp and travels 1.2 meters to the bottom. What is the acceleration as the ball travels down the ramp? Next create a velocity vs. time graph below taking care to label units and numbers properly. Give the equation for the graph in slope-intercept form (y = mx + b).

2. Frankie and Rosie take a trip in a car from one town to the next. During the trip several different average speeds are driven based on traffic. Frankie drives for 16.4 miles at 22.0 m/s, 14.5 miles at 26.0 m/s, and 30.2 miles at 18.0 m/s. As part of this trip Frankie and Rosie stop to eat dinner at a diner for about 35.0 minutes. Calculate the total time for the entire trip in minutes. o straight portion of a track